So I had a 5.7L 350, bored 30 over to a 355. The engine has no power and has a shudder at cruise, also when I rev it in park it has a miss at about 1100 rpms where it runs rough. I tried adding timing, I set the total at 34 then 36, I tried Port and manifold, even no vacuum advance, still runs like crap. The idle sounds good, and it will scream up to 6000 RPMS in park, But once i take it out on the road it has no power. So it runs fine in park except for the miss at 1100 when I rev it.

It has 76cc heads, flat top pistons, a GM performance cam ZZ2 roller cam, roller rockers, Headers, a 750 edelbrock carb, HEI distributor, edelbrock fuel pump, and a Wieand Action Plus intake.

Any help would be much appreciated, Im thinking of throwing on Vortecs or some double humps...

 

I just solved a problem similar to this. My fuel pump was on the way out, and wasn't producing enough pressure. Tested the pressure and found it to be VERY low.Car ran decent in neutral, but in any gear it would stall out almost immediately. New fuel pump and problem solved.

 

76cc chambers aren't helping you make power. The real trouble though sounds like a failing coil or wires. check spark with an inline spark tester on a number of plug wires as you power brake the engine. Look for spark drop out. Of course, check fuel pressure too. Should have 4-7psi at all times.