Ok... I'm pretty new to this so bare with me. I bought a 77 f150 with a 351W in it. Here's the problem. I can get the truck to fire with my foot all the way down on the throttle, and the choke pulled all the way out (it was about 50 degrees outside today). The truck will fire up and run but it backfires and throws flames out the headers, or the carb sometimes. It also is spraying fuel out of the headers while running. I have to keep my foot steady at about half throttle and play with the choke to keep it running but it keeps wanting to die. Do I have a timing issue, a carb issue, or both!? I don't really know the best place to start! Also I think the plugs are probably now fouled due to the large amounts of fuel being dumped into the thing!

 

Since you're getting so much fuel through the engine, I'm going to guess something's wrong with your carburetor. Check to see if its power valve hasn't blown its diaphragm. That will let the engine vacuum suck a lot of gas into the manifold, and the engine will not idle, and run like you describe with more throttle opening. But it will be rich all the way.

 

My guess is, one: you're pumping the gas pedal far more than you should to start it. And two: it needs a complete ignition tuneup (new cap, rotor, wires, plugs) and the timing and carb set afterwards. Where are you located ? It would help to get someone who knows what they're doing to "show you the ropes" instead of fumbling around in the dark.

 

Only pumping the pedal about twice to three times... i really don't think thats the issue. I am located on the south side of indianapolis.

 

You have flames shooting out then you have a ignition problem.

 

You shouldn't have to give it but one or two tops to get it to fire off. Also check for a stuck carb float.

 

Alright first stop and take a deep breath. Go to you carb and turn your mixture screws all the way in. When they get all the way in don't crank them down. Then turn the screws 1 and half turns out. That's what you should start out with. Then bump the engine to top dead center. The best way to check that is to "bump" the engine to where the TDC mark on the harmonic balancer is at 0 on the timing pointer. Then take your distributor and loosen the bolt up on the hold down. It is 1/2 SAE. Take the cap off the distributor and line it up with the number 1 clyinder wire. Which will be the spark plug wire that runs to the clyinder on the passanger side closest to the radatior. That will put your timing at top dead center. Then start the truck. It's gonna run a little rough because your timing is at TDC and your cleaning out all that fuel. Next get a timing light and set your timing with the vaccum advance line plugged. 302's like there timing between 6 to 10 degrees before TDC. That should take care of your problems. If not you could have internal issues. Such as a loose rocker/timing chain jumped a tooth/bad carb. Let us know the results