Help! - 235 won't run when warmed up

I'm at wits end. I have a '58 235 in my '51 PU and for the life of me I cannot figure out what's up. The basics - reman'd engine with clifford intake (heater water routed thru the intake passage) and a small 4-barrel holley; fenton headers with dual exhaust all the way out. I have a mallory dual point distributor with mechanical advance set such that the knock just went away pulling heavy in 4th gear. New plug wires, tried 2 different coils, new distributor cap, rotor and second coil - even tho the distributor was new I thought why not. I had hoped the valves were tight but just checked them and they are ok. I put a fuel pressure gage at the carb and it reads 5 1/2 - 6 pounds.

The engine runs good until it gets warmed up. Then is misses so bad it has trouble rev'ing above 1,800 rpm. No weird noises - nothing. Anyone have any ideas where to go? If it was a horse I would put a bullet through its head.

 

I think I'd head for the Condenser. They will brake down with Heat and can make you loose ign fire. It will carry on like that until it burns the points up.
The Wizzard

 

Thanks - i'll check that out - haven't checked that specifically yet.

 

Thanks all for the feedback. The troubles helped me find several little issues that would have been a problem sooner or later. I did finally find the culprit that kept it from running. Just because the mallory dual-point distributor was new did not mean the points were set correctly. I adjusted the dwell on both sets and it runs great. It's always the simple things.

Thanks again. Ray