holley sniper with msd mod 6 on a 4.6 dohc with c heads
I have been thinking about doing this for years. It was hard to find any information on running a carb with a mod 6 in a ffr cobra let alone tb efi. Because of this I am making this post to help others who want to do the same. There is only one option currently for an intake manifold, Sullivan performance. I kept finding in my searching people saying sullivan no longer makes the intake. That is not true he does still sell them. I finally pulled the trigger. I started the install removing the stock ford fuel injection intake last tuesday and installing the sullivan and sniper for fit check. Yesterday in about 6 hours, I dropped the fuel tank and put in the pump. Did the plumbing and enough wiring to start the engine.
All that's left is hooking up the hi and low fan control from the sniper. Rewiring my tach to be fed from the sniper. cleaning up the trans wiring harness since I no longer need the 02 sensors. Install the the lokar throttle cable and bracket. 15" oval air cleaner.
The install was pretty easy. Using the 98 cobra pump really simplified the fuel system. It comes with the return as well as a non pulse width modulated fuel pump compatible with the sniper. I confirmed this with holley and walbro. I used -6 ptfe stainless hose since where i live they add ethanol to the fuel from time to time which eats up rubber. My dyno tuner told me years ago he has had many customers who's braided stainless hose leaked fuel because the rubber was eaten by the ethanol. He has actually seen rubber extruded through the braids like it was playdough. I love how the epa has required an additive in the fuel that actually causes fuel to leak into the atmosphere and cause pollution. Because I don't want to have a fire hazard on my hands, I bought 20' of ptfe hose which was just enough to do the runs. i had none left over at all. I used the factory hose from the 3/8 tank push connect fitting to the fuel filter push connect inlet. From the filter on I used ptfe -6 hose to the sniper.
For the dohc the mod 6 coil harness wires need to be swapped. The harness is set up for use on a SOHC engine. DOHC engines use coils with reversed polarity. In these applications, the location of two coil wires needs to be swapped in each connector. Pulling the pins and swapping them is not too hard to do. Use a small screwdriver to lift and remove the yellow plastic locking tab. then use a super small screw drive to push in the tab on the connector pin and remove it.
Fyi, I have no spacers under the motor mounts of the 4.6. My motor, fuel tank and computer (which is now disconnected) was from a 2004 mach one
I had the carb mating surface of the intake manifold milled down .375" for extra hood clearance. I spoke to Scott Sullivan about my idea of milling the intake and he said he has had customers who have done it with no issues. I asked how much could i take off. He said there is enough material to remove .5". I only did .375 because I didn't want to cut into the name on the intake. There was enough material but I didnt want to go that far.
using sniper with a mod 6 is not in the sniper manual or the msd manual so before buying everything I called Msd and holley tech support. Msd had no clue. Holley told me to connect the mod 6 yellow wire to the sniper yellow wire and select coil negative no timing control on the sniper. This did not work The engine would start and die right away. I noticed the msd mod 6 yellow wire was a square wave tach signal. It seemed odd that you would use that signal and tell the sniper it was getting a coil negative signal. I noticed there was an alternative setting for a cd box with a tach signal connection. I tried the msd yellow wire tach out to the violet wire on the sniper and selected cd box. The engine fired up and ran perfectly.
The is the correct way to wire the mod 6 to the sniper......The msd mod six yellow tach out wire connects to the holley sniper violet wire. (Set the sniper to cd box no timing control)
my parts list,
sullivan carb intake
msd mod 6
holley sniper
15" billet aluminum air filter with 2" washable element
98 cobra fuel pump with return (make sure its the non california emissions verson. the california version has no return) Walbro tu227hp 255 lph
20' 6an ptfe stainless hose
2) 6an hose to fmale fitting straight (fuel filter end and fuel tank return end)
2) 6an hose to fmale fitting 90 (carb end)
russell 640863 5/16 quick connect to -6 an male (connects to the standard mustang push on 5/16 fuel filter)
russell 644113 5/16 Adapter Fitting to 6 an male (to connect the return from the pump to -6 hose)
K&N PF-2000 Fuel filter (fits stock mustang filter mounting bracket)
dorman 42049 pcv grommet
pcv valve (autozone) duralast pvc1115dl
lokar TC-1000U36 THROTTLE CABLE 36"
Demon 1953 Throttle Cable bracket
pictures with a 15" oval air filter. Fits under the hood no problem. Have about 1/4" clearence to the hood scoop on the passenger side. The drivers side has tons of room.
I just did some adjustment to my msd mod 6 and so far the results are good. since i have pretty aggressive cams I added a quick timing bump from 820rpm to 0rpm to save the motor from stalling if the idle starts to stumble. Works great.
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