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

[mike223]

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.

Just another point of data:

My 1990 block did require a little grinding at the bottom of (at least) most of the cylinders for the 393w crank - specifically it was to provide clearance for the bolt heads on the h-beam rods as they pass the outside bottom edge of the cylinders.

[GoDadGo]

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.

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.

Great Perspective Having Ample Seat Time In Both Cars!

[rezell3d]

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

I want to use the Edelbrock Victor intake on my Windsor build. Will I have any problems with clearance?

[GoDadGo]

I want to use the Edelbrock Victor intake on my Windsor build. Will I have any problems with clearance?

The shortest intake for a 351-W, especially if you are looking for a single plane intake, is the Torker II.

https://www.edelbrock.com/torker-ii-...fold-5081.html

Hope This Helps!

[erstanl]

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.

This was my case as well. My block is an 351W F4TE (1994 truck engine). No clearancing necessary to get to 408 using a cast steel eagle crank.

[CFranks]

My 351-based 427 with rpm air gap intake, carb and oval air cleaner JUST fits under the hood even without the hood scoop (waiting for painter to do that). If I get after it there is the slightest of scrapes but will be plenary of room with scoop.

[Avalanche325]

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.

Yep, it depends on the specific crank and piston combination and how far you are going. The OP sounded a little freaked out about it. But the first time someone sees a clearanced block, they quickly realize that it is no big deal.

[Dwleo]

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. .

I had a 351W built for my Mk IV and love it! Only pulling 370 hp but that's more than enough to have fun with. I'm running a spacer under my slayer and the oval cleaner which just fits in the scoop tunnel with only a slight modification.

[Mugzilla]

Yep, it depends on the specific crank and piston combination and how far you are going. The OP sounded a little freaked out about it. But the first time someone sees a clearanced block, they quickly realize that it is no big deal.

I would put me less than freaked out, but losing some cylinder piston guidance gives me cause for concern. Seems a 347 is on the ragged edge of comfort to make the power that a 351w will. Still earning and absorbing from the great conversation!

[CraigS]

I understand why people go w/ a 347 especially if they already own the car/engine. Because of the taller deck a 351 needs different intake and exhaust headers so they would be an additional expense. But if starting w/ nothing, a 351 costs no more than a 302. And, if you are satisfied w/ about 350 cubes, you can use the stock 351 internals, vs a stroker kit to get from a 302 to 347.

[rich grsc]

I would put me less than freaked out, but losing some cylinder piston guidance gives me cause for concern. Seems a 347 is on the ragged edge of comfort to make the power that a 351w will. Still earning and absorbing from the great conversation!

You're talking about a notch about 3/8" wide and about the same tall on the very bottom edge of the piston wall to clear the rod bolt as it swings past. It has zero affect on piston support.

[NAZ]

It's common on strokers (Ford or Chevy) to require a small relief for rod bolt clearance -- not a big deal if done correctly. Want something important to consider when looking at a stroker -- look at rod lengths. Because the deck height is fixed you have to keep the piston travel within the original cylinder length which will require a piston with a lower compression height, shorter rod, or both. Rod length has more affect than folks realize. A short rod can cause a significant amount of friction and pre-mature wear on rings, pistons and cylinder. That friction also robs a lot of HP.

Rod length has other performance characteristics you should be aware of. Longer rods are less prone to detonation, increases piston dwell at TDC, improves combustion efficiency, and produces more power from mid-range to peak RPM.

So don't fret about block clearance mods but do look closely at rod length when considering a stroker. For example, before I built my latest engine I spent many hours with my modeling software to arrive at the bore / stroke / piston / head combo. Since I was building a nitrous engine I was limited on compression height (same for boosted engines), therefore limited on rod length and rod ratio. My 406 actually makes more peak power than the same basic configuration with 434 cubic inches because I can run a bigger rod ratio with the shorter stroke. There's that much less friction with the longer rod ratio (1.6:1 on the 406 vs 1.5:1 on the 434).

[mike223]

Rod length has more affect than folks realize. A short rod can cause a significant amount of friction and pre-mature wear on rings, pistons and cylinder. That friction also robs a lot of HP.


So don't fret about block clearance mods but do look closely at rod length when considering a stroker.

+1

Here's a good reference: https://www.fordmuscle.com/archives/...ker/index2.php


Also do not be oblivious to compression ratio - lest you build something that runs better on diesel than regular unleaded...

[GoDadGo]

+1
Here's a good reference: https://www.fordmuscle.com/archives/...ker/index2.php

Thanks For Sharing!
I Am Glad I Went With 6.0" Rods Over The 5.7" Rods For My 383.

[NAZ]

Great reference Mike! Particularly for the SBF. And good advice on the compression ratio.

Folks may want to also research dynamic compression ratio if doing their own combining of parts and assembling an engine themselves. The static CR we commonly cite and most pay attention to is only a reference point -- dynamic CR is becomes important when you start pushing the envelope on pump gas. For you amateur engine builder, GTS (Google that stuff) to learn more.

[GoDadGo]

NAZ & Mike223,

I totally missed the boat when it comes to Dynamic CR.
Guess that's the Banker in me, but the car runs very well.

My Static CR Is between 10.00 and 10.125.
I am running iron heads. (Dart 215 CC Intake Runner Iron Eagle Tall Ports With 72 CC Chambers)

383 CID / 4.030 Bore / 3.75 Stroke
6.0" rods in the sucker so my rod angle ratio is 1.6.
12 Degrees initial timing, mechanical advance only, 32 total.

Duration @ 0.006": 288° / 294°
Duration @ 0.050": 236° / 242°
Max Lift w/ 1.5RR: .520" / .540"
Lobe Separation: 110°
Intake Centerline: 106°

Do I have any issues the be concerned about?

[Jeff Kleiner]

Do I have any issues the be concerned about?

You mean other than the distributor being on the wrong end?

Jeff

[Avalanche325]

You mean other than the distributor being on the wrong end?

Jeff

Ha! hahahahahaha!

[GoDadGo]

You mean other than the distributor being on the wrong end?

Jeff

Ha! hahahahahaha!

Correct End For Acceleration Since Da-Sump & Da-Pump Both Get Covered For All Hard Launches.

Totally Wrong End If You Like Stopping More Than Geauxing!

Geaux Tigers!

Geaux Saints!

[NAZ]

Distributor on the wrong end -- that's funny. As a former Ford technician, I have to agree. But working with SBC & BBC engines for so long now it almost looks normal.

Steve, if you don't have any detonation issues now you should be OK until AOC and her friends outlaw 91 / 93 octane pump gas. Dynamic CR is always lower than static as it takes into consideration the point at which the intake valve closes. Compression can't start until all the valves are closed. If you were to add a turbo you might want to revisit your CR or you can change the cam timing or grind to hold the intake valve open longer and lower your dynamic CR.

All is good.

UPDATE:
My bad, I left off some important 411. While the DCR is always less than the SCR, the octane requirement scale is also adjusted when using the DCR. For example, my SCR is 12.97 and my DCR is 10.71. If we were talking 10.7 SCR that would be a pump gas engine with a moderate cam, however, when looking at DCR the requirement is 110 octane minimum and that is also dependent on ECT and alum vs cast iron heads.

But you're still OK on your set-up -- if it's been running good so far, no worries.

[canuck1]

This won't rectify your distributor orientation issues GoDad, but it can be fun to enter your numbers into a calculator to see what you come up with. I have downloaded and use this one frequently:

http://members.uia.net/pkelley2/DynamicCR.html

It's a very useful guide and aid in selecting components, especially camshaft. Make sure to read the technical guide and enter data in the format requested.


Sean

[NAZ]

Canuck1, looks like your attachment must be an old version. Seems like it provides some good info but some of the links to other sites are faulty. David Vizard is one of my heroes and of course I clicked his link first thing. Interesting bunny trail to follow -- not what I expected, but interesting.

[canuck1]

Naz,

An old link, for sure. I downloaded the dynamic compression ratio calculator from there years ago. The link to download Pat Kelley's DCR calculator is still there, but some of the other links are probably not valid.

There are online sources for similar calculators, but I like having it at hand when I'm curious about a combo.

Sean

[NAZ]

Sean, not everyone appreciates my sense of humor. You should check out David Vizard's link but make sure your virus protection is up to date before clicking past the first page. Enter at your own risk.

[rich grsc]

There is no excuse for a chevy, or forgiveness.

[GoDadGo]

There is no excuse for a chevy, or forgiveness.

.Yep, Chevrolet Never Forgives Where I Live.
They Just Win!

https://www.gulfportdragway.com/ford-vs-chevy/

[Howard]

I'm running a Dart block 427W - absolutely love it - running it with Nitto NT01 tires - soooo much fun. Easy to control the rear end with the right foot.

[Mugzilla]

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!

Now I have some thinking to do; If I stroke this thing, I’ll be creating low end torque, which, while fun, can end up NOT being your friend.

[NAZ]

Now I have some thinking to do; If I stroke this thing, I’ll be creating low end torque, which, while fun, can end up NOT being your friend.

It's easier to build power into the engine now than add it later. That skinny pedal modulates the power so don't fret all the talk about tires up in smoke, you don't have to accept that (well, maybe with an IRS). My car has a 6000 RPM stall converter, 3.90:1 rear ratio and on a standard day at sea level will produce over 10,000 lb feet of torque at the rear axle (>600 lb ft of engine torque & >700 HP at 6000 RPM). When I leave from a stop light off the trans brake & two-step there is no drama, no scalded tires up in smoke but it will plant you in the seat with more than 2 G's. The car weighs less than 2500 lbs full of fuel and my pear shaped body in it. It is possible to harness that power and turn it into acceleration with a solid rear axle.

[CraigS]

Now I have some thinking to do; If I stroke this thing, I’ll be creating low end torque, which, while fun, can end up NOT being your friend.

I built a mild 408. I told Comp Cams I wanted to be able to drive at 1300 in 5th. Used their recommended cam. I should probably have gone one step up w/ the cam. But the engine drives perfectly, almost as well as an injected engine. I can drive around at 1300 in 5th or at 1000 in 3rd ambling around in a neighborhood. I also set up my mechanical throttle linkage to have a little more than average pedal travel so I have better control. So I say that, if you want to stroke it go ahead.

[rich grsc]

Now I have some thinking to do; If I stroke this thing, I’ll be creating low end torque, which, while fun, can end up NOT being your friend.

That is the exact opposite of true. Having torque makes it very easy to drive, you don't have to constantly be shifting, and easily rolling into RPM's make for a smooth steady drive.

[Jeff Kleiner]

Every throttle pedal I've ever used operated like a hinge---they swing both ways, up AND down.

Jeff

[GUARDDOGG]

Even if I run a FFR hood scoop?

[rich grsc]

No, you can't run a hood scoop

[NAZ]

Run without a hood. Problem solved. What else can I help you with?

[CraigS]

Even if I run a FFR hood scoop?

What does this mean?

[AdamIsAdam]

I can't help but show off like a proud pappa and add to this thread:

I just had my 347 stroker on the dyno last week. I could not be happier with the performance. FLAT torque "curve" and HP that just points to the sky. This engine is fantastic. It's got 10.5:1 yet starts and runs like it's 8:1. It's got gobs of power everywhere. Yet that 302 block gives me enough room to work on it and looks great.

Oh, and I was really curious to see how badly my 1.75" oval air cleaner was choking it so my runs were: #1) air cleaner on, hood open. #2) air cleaner off, hood open. #3) air cleaner off and hood closed. I made the most power on #3! I suspect it made more power as it got fully heat soaked, but I went up 5hp with each run, making the most with the air cleaner on.

385HP at the wheel, so approx 450+ at the crank. And with 3.55's and a T5 with .6 overdrive (73 MPH @ 2,000 RPM) and it loves to run at all speeds, all RPM's, etc.

https://youtu.be/6hhnwAYj-Jc

https://youtu.be/QboLm0fO7Yo

20201024_152822_(1).jpg

[CraigS]

An Edelbrock Performer RPM (not air gap) w/ this cleaner works fine.
https://www.summitracing.com/search?...rs%20SPE-47622

[Rdone585]

What am I in for?=> too much fun!

Based on my experience with a stock 351W block, don't go too high in HP. If you keep it under 500 HP you will probably be OK. Consider a crank girdle for a measure of insurance. If you want more I'd suggest an aftermarket block that will handle the torque and HP, like the Dart SHP. I tore the block apart where the crack main bearings bolt to the block. Chunks of block floating around the engine = failure. Admittedly this was WOT on the straight at a track, so that equals maximum stress on the 2 bolt mains. All said and done, I say go for it, build the engine of your dreams, you will not be disappointed. If you need an Eagle crank for your build, I have 2 good spares, one for a 351W and one for a Dart SHP. I can share the stories of why if you care to hear.