[CrashFarmer2]

I have a 390 cid FE in my 1972 Ford truck and lately I have been experiencing a problem that I believe is fuel delivery related. When accelerating or going up a big hill if I press on the gas too much it begins to backfire. This backfiring will continue until you let the engine idle for a minute or two. This engine acted exactly this way a year ago when the fuel filter plugged up, I replaced the filter then and had no trouble with it until recently. This time I have replaced the fuel filter, carburator and the fuel pump and still it acts the same. It will run just great until it has a heavy fuel demand placed on it. I'm wondering if I need to go to an electric fuel pump?

 

[crazy larry]

are you still running points? hat do they look like?
whats the timing set at?
any play in the timing chain?

 

[oldschoolrods]

Like larry said it sounds like there could be some play in the chain. Or a bad set of points....and believe me I had a blast with my points :smash: I dont think you'd need to go to an electric pump if it was working fine before

 

[Tmod]

I had this exact problem with my truck (F-250/390) and I replaced all the fuel lines coming from the tank to the pump and it fixed the problem.

Just my experience and .02

 

[Black Sheep]

Is there a filter on the pickup tube in the tank?

How are the rubber lines on the draw side of the fuel system? If it's sucking air, it will behave just as you described. Our '82 Chev shop truck did the same thing...

 

[oldschoolrods]

Only filter I know of on these trucks is on the fuel pump