When I bought the car, I was told it was used for drag racing.which is probably true..no unnessesery stuf under the hood. Anyway, I recently had a new exhaust put on, replaced the Holley with a Q-Jet and put a new HEI Distributer in it.
Car startrs and idles very nicely, but nder acceleration it rattles the valve train something awful, like time way to advanced or water in hte gas and has no power, i have tried both ends of the spectrum on timong with no luck, 2 different distributors,

Some things that have crossed my mind are compression is too high for pump gas, or a bad vacume leaf(but it idles very smoothly) timing 180 of, but i dont think it would run at all..and it doesnt backfire at all.

I would appreciate any thoughts..thanks
Chuck

The rattling could possibly be detonation, timing could be way off as well.

Have you looked at things like unbalanced drive shaft, or worn out/loose engine or transmission mounts?

How does the balancer look ?

Chances are if was used for drag racing the jetting in the Q-jet is too lean for the engine. Why did you take the Holley off? If it was on the engine for any length of time it's probably tuned for the engine or it should have been.

If these problems only started after changing the items that you listed, then most likely your problem is with one of the items you installed, or the way you installed it. Do you know what the actual compression ratio for this engine is?

I would go back and put everything that was on the car before, back on! Then see if you can get it to run properly.

Out of curiosity-why did you change all of those things out to begin with?

What intake is on the motor? What size was the holley you took off? A carb that is way under size will make wierd things happen.

There's alot of things that could be going on. Your compression may be way too high causing detonation. This is my first thought because a drag only engine will run the highest compression possible. Also, when you installed the HEI did you set the timing curve for your compression, cam, gearing, etc., or just drop it in? This could be a major problem also. Is the Q-jet calibrated for your engine or just an out of the box rebuild or old stock carb? Another problem. Put the holley back on and some race gas in the tank and see what happens.

well..it seems cam lobe wore down..