I have a 67 C10 with 350 crate motor with about 5000 miles on it, my issue is at wide open throttle the motor breaks up, normal driving runs smooth, can drive 70 mph down highway and no problem, punch it and no power, bust up. Have changed carburetor, all parts in HEI distributor, spark plugs and wires, fuel pump, fuel filter, have put timing everywhere and nothing has helped, I’m at my wits end. Could my problems be mechanical?, lifter, timing chain, ... any help would be truly grateful.

 

What do you have for exhaust? Do you have headers? If so do you have it balanced properly. As in proper H-pipe...

 

I have Sanderson headers, turbo mufflers that dump before rear end and no H or X pipe. Thank you for replying back to my thread.

 

what type of fuel pump and carb are you using?