Okay guys this is a question for my friend I have tried everything I know and we can't get his car to run right so hopefully you guys can. He has a 1989 camaro with a carbed chevy 355, AFR 190's, 10.5:1 compression, XE268H cam, RPM Airgap intake, and topped off with a Holley 750 cfm 4150HP carb he bought used all run through a muncie 4 speed an moser rearend with 3.73's. Now I expect this thing to at least make 400 hp at the fly minimum. We have only put 20 miles on it in the process of tuning so it still hasn't been broken in completely we plan to run it hard for the break in. Anyways this car has no power whatsoever under 3000rpms feels like a 4 banger and even after that it still won't pull harder than what feels like 250 horses to me. Our biggest problem is that we can't seem to get this thing to get more than 1.5 inches of vacuum. We called compcams and they said this cam should pull between 13-15 inches of vacuum. We have sprayed every gasket area with ether many times to see if we have a leaky gasket and nope gaskets are sealed the carb baseplate gasket has been replaced once to be safe. Then we ran a compression check on all the cylinders and they were all great. We readjusted the valves with the car running and that helped our back fire through the carb problem. We have set the intial timing at around 12 degrees, and checked to make sure the cam was installed straight up which it was. After all this we managed to go from .5 inches to 1.5 inches of vacuum. I am at a loss what else could we check. I was thinking that the only thing left is the carb. I have tried to set the idle with a vacuum guage but get no response when I turn any of the 4 idle cirguit screws and the car will stay running with all them pinched off so I am thinking blown power valve. What do you guys say? I am dead out of ideas except for trying a different carb on there and seeing if the carb itself is the problem.
