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Thread: I want a 351W. What am I in for?

  1. #1
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    I want a 351W. What am I in for?

    If I am building a FFR Mk4 roadster, I am going to do something "greater than moderate" with the engine. I've had fox body mustangs with the 302, and they were fun. I can't wrap my head around the 347 and the way you have to relieve the block, and the way the bottom ring protrudes when the piston is down.

    I want a 351W.

    Can anyone make any recommendations? Things to look out for? Blocks to look out for? Reputable engine builders for a short block?

  2. #2
    Senior Member CFranks's Avatar
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    I have a Ford racing 427 based on a 351 Boss block, came from Mike Forte who I’m sure you’ll see will be recommended very highly on this forum. As to what you’re in for.... it’s awesome, sounds great, looks great, runs great, awesome low end torque. Just be prepared for horrendous gas mileage if you stroke it (if that matters to you).
    MK IV Roadster #7999
    Ford Racing 427x; QF 670 Carb; TKO 600; 3.31 Rear End; 3-link; 17” Halibrand Replicas (9” front, 10.5” rear), Khumo Ecstas (245 front, 315 rear), EPAS Power Steering; Power Brakes; 8/1/19 - Legal in gelcoat!; 12/1/20 - Paint & bodywork in progress! Silver, no black, no red, wait now silver....

  3. #3
    Senior Member Gordon Levy's Avatar
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    351 base is a nice package. Stage 4 version from me is a solid 450hp. The strokers are as much as 610hp on pump gas and can be driven daily. Really depends on what you want out of your car.
    99/2000 NASA PSO Champion-2005 west coast FFR challenge series Champions
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    Senior Member KDubU's Avatar
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    The 351w is a great engine and either Mike Forte or Gordon Levy can build you one that you will enjoy. I went with it over the 347 as I thought I may want to stroke it later on plus the $ diff was minor. A 347 is great in the these cars as well as long as you have a good builder.
    Kyle

    Complete Kit pickup 09/05/2015, 351w, QF680, 3.55, 3-Link, 15" Halibrands with MT's, Painted Viking blue with Wimbledon white stripes on 03/15/2017. Sold in 08/2018 and totally regret it.

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    I am researching a non-stroked 351W. I am not a fan of assembling the lower end; I don't need to "refresh" my marginal experience on an engine that I expect performance out of. Heads, intake, and accessories are fine. I believe I still have a set of AFR185 heads in the shed.

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    I just recently finished a build with a 351W. I used the AFR185 heads and forged internals. Engine is internally balanced and with a nice Isky cam, the Fitech just sits on top and screams when I want it to and putters along the rest of the time. My mileage on the highway is 18 MPG. I'm not worried about mileage with this car, but I have to say I was surprised on my first road trip. The longer I drove, the better the Fitech ran. I'm at 10.5:1 compression and right at the limit on pump gas, so keep that in mind. Too high of compression and you will have to source race fuel to support your habit. The torque on a 351 based motor "feels" like it comes on sooner than my old 302 based motor (with AFR heads). That's measured at the base of my spine when I smack the loud pedal. As stated above. Talk to the forum vendors and tell them what you want. You will not be disappointed.

    Scott
    Built FFR9457. 351 Windsor, TKO600, 3.73. Fitech EFI. Russ Thompson throttle pedal, turn signal, and trunk pan. Carbon Fiber dash with Speedhut Revolution gauges. Paint by Jeff Kleiner.

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    Senior Member edwardb's Avatar
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    A 351 block is a good choice. Many on here will support and recommend. Just watch the height on the intake, carb, air cleaner, etc. Easy to run out of height there and be against the hood due to the increased deck height of the 351 block.

    Also, just for the record, the comments you made about the 347 aren't the case if done properly. Relieving the block isn't a big deal, unless you use an aftermarket block like I did. Which is now routinely recommended anyway. Also, with the right pistons and block the rings aren't coming out the bottom of the bore. A 347 is also a good choice and a proven setup. Just saying.
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    Senior Member FF33rod's Avatar
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    You asked about a short block. Check Levy and Forte as mentioned. I used TRE Performance for a 347 short block, top end kit ,... also Blueprint is a great way to go, they are extremely helpful and know what fits in the various FFR kits
    Steve
    Last edited by FF33rod; 12-02-2019 at 08:58 AM.
    Gen 1 '33 Hot Rod #1104
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  10. #9
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    I used an Engine Factory 351w based 427w. Nice power and sound. As Edwardb states you can run into issues with under hood clearance. Not a problem if you're using a hood scoop. One caution I have is the oil pan. I have seen some builds, not always FFR's at car shows where the engine builder used a pan that hung below the cross member. Not a good idea. Other than that they have an unmistakable rumble, fit nice and neat, and have ample power. Good luck.
    JRL16
    Mk4 delivered 4/28/16. First start 10/15/16. First gocart 11/10/16. Engine Factory 427W. 750 carb. Tremec TKO600. 2015 IRS. Power steering. Whitby power brakes. Wilwood brakes. 18" wheels. Falken tires. Sway bars front and rear. Forte hydraulic clutch and mechanical throttle linkage. Scott's Hot Rods triple reservoir. Ceramic coated headers. Gas’n sidepipes. Heated seats. Herb Fraser walnut door panels. Wipers. Console.

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  12. #10
    Not a waxer Jeff Kleiner's Avatar
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    Quote Originally Posted by edwardb View Post
    ...Just watch the height on the intake, carb, air cleaner, etc. Easy to run out of height there and be against the hood due to the increased deck height of the 351 block...
    Agreed. Stay away from the Performer Air Gap intakes or others of the same height and hood to air filter clearance will be OK.

    Jeff

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    Quote Originally Posted by Sdonnel View Post

    I'm at 10.5:1 compression and right at the limit on pump gas, so keep that in mind. Too high of compression and you will have to source race fuel to support your habit.
    GoDadGo and I both stroked 350/351 engines (to 383/393) and went with ~10.5:1 compression.

    We've decided if we ever have to build them again we'll stay at 350/351 displacement and a lot more like 9:1 compression.

    That's for 200TW street tire / street car use - we've concluded we would be just as happy with a little less HP/TQ and run it on regular gas too (bonus).


    It's literally a question of how fast do you want to be going in third gear and still spin the tires at will? (it sounds like more fun than it actually is)

  15. #12

    Steve >> aka: GoDadGo
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    Quote Originally Posted by mike223 View Post
    GoDadGo and I both stroked 350/351 engines (to 383/393) and went with ~10.5:1 compression.

    We've decided if we ever have to build them again we'll stay at 350/351 displacement and a lot more like 9:1 compression.

    That's for 200TW street tire / street car use - we've concluded we would be just as happy with a little less HP/TQ and run it on regular gas too (bonus).


    It's literally a question of how fast do you want to be going in third gear and still spin the tires at will? (it sounds like more fun than it actually is)
    Amen Brother Mike, Amen!

    https://youtu.be/CaRlqMmKIzk

    I scared myself the other day when wheel spin occured in 4th gear because it was a little cool (65 F) on that day.
    Last edited by GoDadGo; 12-02-2019 at 12:42 PM.

  16. #13
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    I have a 351/427 with an Air Gap intake and an FiTech. Had to go to an 8x1.5" filter (no-drop lower because of the fuel fittings) with a filtered lid to stay inside and under the scoop. With a wingnut, had 1/4" clearance to the inside of the scoop. Changed to a bolt and now have about 1/2".

    However, plenty of clearance around the sides to do whatever (plugs, header bolts, etc).

    Just be careful what combo you choose with a 351.
    ---Boyd---
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    Quote Originally Posted by GoDadGo View Post

    Amen Brother Mike, Amen!

    I scared myself the other day when wheel spin occured in 4th gear because it was a little cool (65 F) on that day.

    Yeah, that's another part of the (same) question - Do you really want to wag the tail in 4th gear?

    Careful what you wish for...

  18. #15

    Steve >> aka: GoDadGo
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    Quote Originally Posted by mike223 View Post
    Yeah, that's another part of the (same) question - Do you really want to wag the tail in 4th gear?

    Careful what you wish for...
    No, I Didn't Expect The Snake To Strike!

    I snuck out to make an less than legal drive on the highway the day that LSU played Al-Er-Bam-Er.
    I figured no Purple & Gold Bleeding Louisianian would be on the roads and they weren't so I let her rip.
    At 3,500 RPM's 4th gear got interesting and Thank God I still have the rev limiter set at 4,300 so it settled quickly.
    Though I'm only making around 450 HP with similar torque figures, the 3.73 ring and pinion makes every gear shift interesting.

    3500 RPM + 4th Gear = 72 MPH
    4300 RPM + 4th Gear = 89 MPH
    Last edited by GoDadGo; 12-02-2019 at 02:59 PM.

  19. #16
    Senior Member canuck1's Avatar
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    I built my own 351w (stroker). I like it, but if I was starting from scratch, I'd opt for a 5.0l/302 based engine rather than the taller, wider 351w type.

    I like the horsepower, but you can easily get plentiful hp from a 347. The boatloads of torque that come with a longer stroke just isn't required in a light car like this, imho. I have often considered the 331 or 347 stroker as a better setup. Everything that's available aftermarket is made for the 5.0l based engines. It's not that they don't make distributors, induction systems or headers for 351w engines, there's just a lot fewer out there, so you often need to be prepared to pay a little more and sometimes wait a little longer. I have a MKIII chassis that was built to fit the girth of a mod motor, but I still can't get my hand in far enough to pull the plug wire on #8. I need to do it from underneath. I still had to form some extra clearance on the driver's side to keep my header tubes off the aluminum. There are real limitations on air cleaner clearance you can work around, but these aren't an issue with the shorter 5.0l engine. Some people claim 70-74 351w blocks are a heavier casting (more durable), but roller lifter capability didn't arrive for the 351w until 94. That's another workaround you won't need to figure out if you start with a 5.0l block. While I have no trouble revving mine to 6,000 rpm, the bigger diameter main journals in the 351w don't truly lend themselves to extended high rpm operation. If you are building a track car, this is something to think about too. Don't get me wrong, I like it, but as someone who likes to tinker and experiment with different intakes, heads, headers etc., I think I would have had an easier time all along if I'd started with a 5.0l engine. I'd probably opt for the shorter stroke 331 and build it for bulletproof high rpm operation. I'd happily trade away the torque if that meant I could do away with some of the other things you simply have to endure when choosing the 351w.

    My opinion only, I suspect not a popular one, but you get what you pay for!

    Sean
    MK 3.5 roadster (MK IV body retrofit to MK III chassis) 396W stroker, 4 bbl mass air EFI, QH (self-tuned), AFR 195CC Renegade, XE274HR, GP 4-1-4 SS headers, 3link, 3.73, 15" Halibrand replicas, SAI mod, bumpers, 2 X roll bars, I² electronics, PS, hydroboosted brakes: 95 GT front, custom MK VIII calipers/Cobra discs rear, FFR front, Levy rear LCA's, Forte front, VPM rear bars, CF dash, mod comp layout w/Auto Meter Ultra-Lites, Lucas tri-bar headlights, coupe taillights, painted by SRP (again!)

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    I've had my 351w/427 in for test fitting and development.
    You'll need a low manifold and air cleaner to get it all to fit under the normal hood and scoop.
    I have no expectations of being "normal".
    Jim

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  22. #18
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    Quote Originally Posted by GoDadGo View Post

    I figured no Purple & Gold Bleeding Louisianian would be on the roads and they weren't so I let her rip.

    At 3,500 RPM's 4th gear got interesting and Thank God I still have the rev limiter set at 4,300 so it settled quickly.

    Though I'm only making around 450 HP with similar torque figures, the 3.73 ring and pinion makes every gear shift interesting.
    I think you're going to want a taller gear when you start spinning it up to 5300~6000 rpm.

    I started with a 3.55 gear @ 6500 rev limit + changed to 3.15 gear @ 6000 rev limit.


    Because I didn't like (at all) wagging the tail while gently rolling in to half throttle in 3rd gear.


    Now I actually have to "get after it" to wag the tail in 3rd - 2nd bumps the rev limiter around 68-72mph.

  23. #19
    Senior Member rich grsc's Avatar
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    Quote Originally Posted by mike223 View Post
    I think you're going to want a taller gear when you start spinning it up to 5300~6000 rpm.

    I started with a 3.55 gear @ 6500 rev limit + changed to 3.15 gear @ 6000 rev limit.


    Because I didn't like (at all) wagging the tail while gently rolling in to half throttle in 3rd gear.


    Now I actually have to "get after it" to wag the tail in 3rd - 2nd bumps the rev limiter around 68-72mph.
    I've said before, with these light cars and big HP, low gears aren't the right fit. If I had that HP, a 3:15, or 3:27 gear would be my first choice.

  24. #20

    Steve >> aka: GoDadGo
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    Quote Originally Posted by mike223 View Post
    I think you're going to want a taller gear when you start spinning it up to 5300~6000 rpm.
    Quote Originally Posted by rich grsc View Post
    I've said before, with these light cars and big HP, low gears aren't the right fit. If I had that HP, a 3:15, or 3:27 gear would be my first choice.

    3.73's is where I need to be since my 5th gear overdrive is a .75 with 6th going all the way down to .50.
    This equates to 1,700 RPM in 6th which scoots the car to 70 MPH or 3,400 RPM at 140 MPH.
    No matter what speed I'm going the car has the perfect gear for cruising.
    The happy operation range is 2,000-6000 with Redline at 6,500.
    I just need to learn how to drive the sucker better.
    Last edited by GoDadGo; 12-03-2019 at 08:33 AM.

  25. #21

    Steve >> aka: GoDadGo
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    I really think you can't go wrong with a 302, 331, 347 or a 363 combo of the short deck engine; however, the 351 Windsor just looks really great and fills the engine bay nicely.

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    I’m running a victor jr intake on my 461w with a 11” Randy’s racing filter spun aluminum base that I trimmed to be a little lower with a 2.12” tall k&n filter with a k&n filter lid and it fits in the scoop just fine. My oil pan bottom pan is level with the frame rails using the FFR energy suspension poly mounts. When you do your body work and figment just make sure to shim the motor first to make sure the filter fits in the scoop. Once this is done you can then fit the side pipes. I can 100% guarantee you can can run a air gap style single plane intake. Just if you go this route know the pros and cons of such a set up. Personally I suggest going at leat with a 351w if not a 408w or 427w. You can get short blocks through turn key engines through any reputable vendor. It’s easy to make a little more power now and control it with the little flat pedal on the right, then to go back into a motor to make more later. Plus the stock 351w block is much more stout then a stock 302 block.
    Mk4, Moser M88 rear end, Eaton truetrak, Craft Racing 461 Windsor, MMR pro trans, Glenn’s 1,000 hp cobra fuel system and lots of other parts.

  27. #23
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    https://www.secondstrike.com/technic...leanercalc.asp

    Use the link above to calculate the affect your short air cleaner is having on your engine's performance.
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  28. #24
    Senior Member CraigS's Avatar
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    A couple of thoughts on 351/408. If you want to stay relatively mild you can use the stock crank and rods. They are significantly stronger than 302 parts and they have one size larger bolts than a 302. Just have them prepped and balanced. Use a set of hypereutectic pistons to get 9.5 to 10-1 CR. Top end kits incl heads, valves, springs, cam etc from companies like Edelbrock easily get you 400+ HP.
    https://www.edelbrock.com/shop/power...=3631&efs=3697
    I have a Performer RPM (not air gap) on mine w/ this air filter
    https://www.summitracing.com/parts/spe-47622
    and have never had a clearance problem. Concerns about the wider overall width are likewise over blown. I made mine into a 408 4 years ago. Yep I know the left rear spark plug is a little harder to get to, but I haven't needed to go there in these 4 years. So don't worry about it. Oh, I halved the price of my cam, springs, pushrods kit by going non-roller. I used break in oil and break in additive for the first 500 miles and just break in additive for the subsequent oil changes. I started w/ a 331 rear gear for the 351 and left it w/ the 408. When I did the IRS upgrade I couldn't find a 331 so got a 315 for a better price since no one seems to want them. The 408 probably could have used a one step wilder cam because I can go around neighborhood corners in 3rd at 1200 and drive away. This engine w/ a TKO 500 w/ stock gears (same as a T-5) is a fantastically street-able engine. I take people for rides and drive around at 1/2 throttle for a while. When the situation is right I ease up to 2500 in second and nail it. As the rear end wiggles all the way through 2nd, the reactions vary depending on their back round, from laughing their *** off to a look of fright. I love it.
    FFR MkII, 408W, Tremec TKO 500, 2015 IRS, DA QA1s, Forte front bar, APE hardtop.

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  30. #25
    Richard Oben's Avatar
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    Bone stock 351 lower end with TFS cam and heads can run mid 11s on street tires, YES, Street tires. One of our customers ran 11.73 all day on BFG 255 60 15s, but he is also an excellent driver. Stroked 351 cars almost need a way to de torque them. Lower numeric gears, short intakes (good for clearance). This is all to make them more drivable. I know there is no such thing a too much HP but as stated above the tires breaking loose in 3 gear can be a bit of a scary thing. I have driven all kinds of power in these cars 302, 351, 408, 460+ big block. A lot of torque in a 90 inch wheel base requires max attention. It think the sweet spot is between 350 400 at the wheels max. More can be fun but a bit much. JMHO, Richard.
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  32. #26
    Senior Member Avalanche325's Avatar
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    Quote Originally Posted by Mugzilla View Post
    I can't wrap my head around the 347 and the way you have to relieve the block, and the way the bottom ring protrudes when the piston is down.
    1. The relief in the block is a tiny knotch about the size of the tip of your pinky in the piston skirt and edge of the block.
    2. The rings do not protrude out of the cylinder. On some pistons, the oil ring goes through the wrist pin hole. It is not even remotely an issue.

    Guess what you have to do to a 351 when you stroke it? The exact same thing.
    Last edited by Avalanche325; 12-03-2019 at 11:33 AM.

  33. #27
    Senior Member TBull's Avatar
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    Using a boss block or a dart block, you can have a 347 big bore. Great rod angle too. Crank and rods from 331 with 363 pistons. No wobble at the bottom of the stroke, great power and no clearance issues with the hood. Just as an alternative.
    FFR #4402 MKII Supercharged 308 445 RWHP Sterling Grey W/ Black Sapphire Stripes, Purchase 8/22/2008 Sold 12/04/2018
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  34. #28
    Senior Member Avalanche325's Avatar
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    Quote Originally Posted by GoDadGo View Post
    I scared myself the other day when wheel spin occured in 4th gear because it was a little cool (65 F) on that day.
    What tires are you running?

  35. #29

    Steve >> aka: GoDadGo
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    Quote Originally Posted by Avalanche325 View Post
    What tires are you running?
    Nitto 555's 285/40-17 with a 300 treadwear.

    A softer tires would help; however, I like the taller sidewalls.
    Almost gives my car that 15" look since I'm sporting 245/45-17 up front.
    I had them on my Old Beloved 1995 C-4 and loved them, but that car only made 300 HP & 330 Torque.

    Owned The C4 From 1995 until 2018
    https://youtu.be/svZX2BMSDEs
    Last edited by GoDadGo; 12-03-2019 at 04:15 PM.

  36. #30
    Senior Member Avalanche325's Avatar
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    Well, you know the deal. Stickier and wider is what these cars need from a performance and safety perspective. Personal opinion is 200TW for over 300hp.

    To the OP.
    351, compared to a 302 what are you in for.
    1. A little more expensive.
    2. A little less clearance. All been done before, so no big deal.
    3. A bit more power at stock CI.
    4. A little more weight. Static and rotational.
    5. There is some more strength which is good, but the larger journals have higher bearing speed which is bad. Nothing in life is free.
    6. Calmer engine at a given HP.

    The reason that a lot of builders are going to aftermarket blocks for engines that are not high HP or larger CI, is that good non modified blocks are getting harder to come by. Get a DART or Boss block and it is good. Straight, no cracks, etc.

    I have a stock block 347 putting out around 500hp. I autocross and track along with lots of street, so it gets driven hard. These days, I would probably do a DART block 427 to get the same or a little more power and be a little calmer. (and to put my 427 badges on that have been on my desk for 5 years - LOL) My engine is fairly radical and VERY loud. The loud gets old pretty quick. That adds about $2200 IIRC and a little weight.

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    NAZ, With the filter lid I measured the actual filter area not including the wicking of the molded rubber up the filter and the carb stud mount on the lid. I have a total real filter surface area of 98 square inches. This is with in 1 square inch of running a 14” x 3” filter. I have 1/2” - 1.25” of clearance up top on the scoop. Plus it’s been dyno proven that surface area does not mean as much as directional flow and minimum height over the carb. Engine masters did a dyno shoot out showing this. With an equal surface area and a potential for better directional flow I expect to be not to far off there 14 x 3” k&n data, which is recommended for 675hp. My plan is to do some tuning in the spring so I’ll do a with and with out filter run for comparison. I expect to loose power as you just about always do with a filter but how much can only be proven on a dyno. A theoretical calculator is great I just trust real world results from a dyno testing more.
    Last edited by GFX2043mtu; 12-03-2019 at 04:17 PM.
    Mk4, Moser M88 rear end, Eaton truetrak, Craft Racing 461 Windsor, MMR pro trans, Glenn’s 1,000 hp cobra fuel system and lots of other parts.

  39. #32
    Senior Member Avalanche325's Avatar
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    The Engine Masters air filter shootout was very interesting. I love that show. It certainly shows a lot of old school rules to be nothing but old wives tales.

    I think what GFX is talking about it this:
    They put a round K&N filter on and did a run. Then they put the K&N filter top on and gained power. Then they taped off the outside of the filter, so all of the air was coming through the filter top. That run was the same as everything open, showing that it was sucking all of the air through the top.

    I really should ditch my Cobra oval for a top filter.

  40. #33
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    Thank you all for the input! Y'all even got into gear ratios!

    I think a 351 will be in my future. I'll keep the compression down to sacrifice "some" torque to aide in not breaking the tires loose in 3rd gear!

  41. #34
    Seasoned Citizen NAZ's Avatar
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    Since the importance of flow direction into the carb main body was brought up, there's another thing to consider when dealing with hood clearance issues and short air cleaners. Rule of thumb: you need minimum 2" clearance from the bowel vent tubes to the top of the air cleaner cover for the vents to work properly (may not be an issue if using the open top style filters). Less than 2" (this is not a hard measurement) and you can see fuel bowel level deviations causing mixture variation. A more restrictive filter (or heavier breathing engine) and this 2" minimum may increase.

    Want to do a real hood scoop and it gets way more complicated as critical speed comes into play.

    And one last thing -- dynos are great tools and may provide even more accurate info on filter restrictions (and other performance variables) than a calculator or modeling program can. However, dynos are static testing devices and WILL NOT simulate actual conditions an engine sees in a car. That includes air filtration devices. So just take that into consideration -- a dyno is a powerful tool but is not giving you actual in-use performance data like a drag strip will. I often see folks rely on dyno numbers as if that was the touchstone for all things engine performance wise. Until you can simulate acceleration and aero effects on a dyno you will have to take their limitations into consideration.
    Dart Little M 406" SBC 800 HP N/A & 1,100 HP on nitrous, 2-spd Powerglide with trans brake, 6,000 RPM stall converter, narrowed Moser 88 3.90:1 spool with 35-spline gun-drilled axles & Torino bearings, custom parallel four-link, custom tube chassis & roll cage NHRA certified for 8.5-sec (only two FFR Hot Rods have this cert).

    33 Hot Rod Super Pro Drag Racer Build: 33 HR NHRA Cert Roll Cage Build

  42. #35
    Senior Member Avalanche325's Avatar
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    NAZ,
    Now that you brought vent tubes up. I have told this before, but it is a good warning.

    I used a Cobra oval air cleaner as many of us do, on a Quickfuel Q series. It has flat topped vent tubes. The stock filter is very short. I was having severe flooding issues after my engine got warmed up. The filter top was so close to the vent tubes that it would seal them off when getting hot. I went with a taller S&B filter and all is well.

  43. #36
    Senior Member johnnybgoode's Avatar
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    Quote Originally Posted by Avalanche325 View Post
    The Engine Masters air filter shootout was very interesting. I love that show. It certainly shows a lot of old school rules to be nothing but old wives tales.

    I think what GFX is talking about it this:
    They put a round K&N filter on and did a run. Then they put the K&N filter top on and gained power. Then they taped off the outside of the filter, so all of the air was coming through the filter top. That run was the same as everything open, showing that it was sucking all of the air through the top.

    I really should ditch my Cobra oval for a top filter.
    And the Salad Bowl came second! MT the best $5/mo. I spend! Scott

  44. #37
    Senior Member johnnybgoode's Avatar
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    Quote Originally Posted by CraigS View Post
    A couple of thoughts on 351/408. If you want to stay relatively mild you can use the stock crank and rods. They are significantly stronger than 302 parts and they have one size larger bolts than a 302. Just have them prepped and balanced. Use a set of hypereutectic pistons to get 9.5 to 10-1 CR. Top end kits incl heads, valves, springs, cam etc from companies like Edelbrock easily get you 400+ HP.
    https://www.edelbrock.com/shop/power...=3631&efs=3697
    I have a Performer RPM (not air gap) on mine w/ this air filter
    https://www.summitracing.com/parts/spe-47622
    and have never had a clearance problem. Concerns about the wider overall width are likewise over blown. I made mine into a 408 4 years ago. Yep I know the left rear spark plug is a little harder to get to, but I haven't needed to go there in these 4 years. So don't worry about it. Oh, I halved the price of my cam, springs, pushrods kit by going non-roller. I used break in oil and break in additive for the first 500 miles and just break in additive for the subsequent oil changes. I started w/ a 331 rear gear for the 351 and left it w/ the 408. When I did the IRS upgrade I couldn't find a 331 so got a 315 for a better price since no one seems to want them. The 408 probably could have used a one step wilder cam because I can go around neighborhood corners in 3rd at 1200 and drive away. This engine w/ a TKO 500 w/ stock gears (same as a T-5) is a fantastically street-able engine. I take people for rides and drive around at 1/2 throttle for a while. When the situation is right I ease up to 2500 in second and nail it. As the rear end wiggles all the way through 2nd, the reactions vary depending on their back round, from laughing their *** off to a look of fright. I love it.
    2X I run the standard non air gap Performer RPM intake as well and it makes great power with no clearance issues. I even have enough room to run a 1/2" spacer. Go with a nice mild 408 kit, you will be very happy. https://www.youtube.com/watch?v=vAuWJqgNFI4 Scott
    Last edited by johnnybgoode; 12-03-2019 at 07:05 PM.

  45. #38
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    Quote Originally Posted by Avalanche325 View Post

    Now that you brought vent tubes up
    Heh - if you understand vent tubes, you won't be able to "unsee" the Holley Avenger vent tube.

    Along with the typical "whistles" - this prevents heavy acceleration, or mostly heavy braking (and to a lesser extent other g force) related flooding / rich conditions.


    (no I'm not selling them, lol)


    Couldn't get image to load - search google.

  46. #39
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    I just finished helping my brother build his Mk3.1. I built a pretty mild 351 with stock crank and rods, but used AFR 185 heads. It made 475 HP at 5800 rpm. Here's the kicker. We used an Edelbrock RPM Air Gap dual quad intake with dual Fitech throttle bodies and an oval cobra style air cleaner. It fits nicely in the scoop recess. I had to cut the base and reweld the holes because the Edelbrock intake has the mounting pads closer together than the cobra intakes. But that gave me an opportunity to slide the whole assembly further forward providing clearance for the Vintage air A/C box. I'm sure the filter is quite restrictive at high rpm, but you'll never see that on the street and you can always remove the air cleaner at the track If you're chasing that last 25 hp.

    So, I've driven his car quite a bit and can offer an opinion. My car has a 347 making over 500 HP at 6700 RPM. The 2 cars drive much differently. His has 4.10 gears, mine 3.55. I like the way his car cruises at low speed because of the gears, but at hwy speed mine is much happier. As far as acceleration his car is violent but hits the rev limiter very quickly in any gear. My car comes on less aggressive and pulls harder to a much higher rpm, which I believe keeps the tires hooked up a bit better. So to me anyway, this confirms that gobs of low end torque is not your friend in one of these cars. So, I quess the bottom line is build what you want and learn to drive it.
    Mk IV Roadster, 347/516 HP, 8 stack injection, Holley HP ECU, Astro Performance T5, 3-Link 4.10 gears, A/C, PS, PB Purchased 08/2015, Graduated 02/2017

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  48. #40
    Senior Member CraigS's Avatar
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    Quote Originally Posted by Avalanche325 View Post
    1. The relief in the block is a tiny knotch about the size of the tip of your pinky in the piston skirt and edge of the block.
    2. The rings do not protrude out of the cylinder. On some pistons, the oil ring goes through the wrist pin hole. It is not even remotely an issue.

    Guess what you have to do to a 351 when you stroke it? The exact same thing.
    My 84 block did not need any grinding w/ my 408 kit. Could be that different brand cranks vary whether they need it or not.
    FFR MkII, 408W, Tremec TKO 500, 2015 IRS, DA QA1s, Forte front bar, APE hardtop.

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