Good point Y2K. Could also be the vacuum advance hose is disconnected, not connected correctly, split, or leaking at a port. With the engine running on base timing, it would be a real dog until the rpm's climb and the centrifugal weights in the dist. take over.

I had a 350 in a 69 Chevelle years ago with a Carter 600cfm on top. It always ran stongest with 16 to 20 degrees advance. It sounds like when they set it up after the tune they dropped the advance and leaned out your carb. Fatten up the mixture (go richer) a little at a time and advance timing a little at a time...adjust idle and it will come back. Are you running electronic ignition? If not the dwell should be checked to ensure it is ok...mine liked about 30 degrees...then set timing/adjust fuel mixture and idle.

I got them too look at it again and talked to the head guy there (he has a mean firebird that they drag race). they ended up going with a 36 degree total advance which is much much better now. i went ahead and double checked the vacuum adavance again to be sure.

I still have issues with stuttering while accelerating, but I have had those no matter where the timing is set. I am pretty sure it is the carb itself, 600cfm edelbrock. I am looking at a 750 holley to replace it.

thanks for all the help from everyone

we set our 350's at 28 degrees with no vaccum advance. they were setup to run wot only, but we didnt have any problems. also, when you do fix the problem, make sure your power valves arent blown out. any backfire through the carb can cause the powervavle to break

wait power valve? where is that located and what does it do? I havent heard of that. if it is messed up how will I know?

when i had my 350 in my camaro it stuttering while accelerating at low rpms the past owner put in a cam i also brought it in to get the timing adjusted and i had all the same problems u were having so i brought it back and same then to another shop to make sure it wasnt just the macanic same then the he told me that the after market cams would do that if it has a stock toruqconverter and stock gearing i then pull the motor and put in my 383 :) i like that much more