I have a 77 f150 4x4 with a 351m. The engine has stock compression, heads and ignition.It has the comp cams 268h cam kit (camshaft,lifters, springs, timing chain etc), edelbrock performer non egr, and the holley 670cfm street avenger. For the last couple years it has runs great. Starting like two weeks ago my truck will die while driving on the freeway( between 50 to 65 mph), then it will start right away. My dad had the same problem years ago with this truck (different engine) so I did the same thing to try to fix it. I removed and cleaned the fuel thank, along with the fuel pickup filter. No difference. Then I took my own aproach, I replaced the stock fuel pump with a new one with the same results. How ever I installed a clear inline filter in front of the carb and noticed that It was never filled more than half. So I kept thinking this was still caused by a fuel delivery problem. Quick call to summit racing and ordered a 60 gph holley street pump (7 psi). I installed the pump the clear filter is full now all the time, but I still have the same problem. Fuel delivery is not the cause ( at least up to the carb), I replaced the old k&N airfilter with a standard paper one ( could never cleaned the K&N to work as new), reset the carb idle mixture screws with a vacuum gage and set the fuel level to 3/4 level on the sight plug (front & back). With the same results.
Now the truck has started to die even at low speeds and sometimes it takes more than 3 tries to start again. Some times the carb spits fuel trhough the top after it dies. What do you guys think might be the problem? I know bad timing will cause a carb to spit fuel after you turn the truck off, could that be the answer? Any help will be greatly appreciated guys. Sorry its long.

 

I'd be willing to bet it's the ignition. I think you'll be replacing the Duraspark module before you're done.

 

Should I stay with the duraspark setup, or will this be a good time to upgrade to an aftermarket one perhaps an MSD. I was almost sure it was an ignition problem after all my other attemps failed. I have an extra module from my 77 F100 swb that I'm building, I'll try that one on in the next hour and see what happens. Thanx

 

Looks like the module from the short bed did the trick, it has run fine for the last hour. Thanks bill_.