I have a 1971 Corvette with a 350 that I had rebuilt in 1988, but it oly has 1,000 miles on it. I had it in storage all of these years. Anyway, when I got it out I gave it a tune up and drove it for 50 or so miles and it began running rough. I checked the plugs and they were wet and black. I proceeded to changed the Carb to a newEdelbrock 600 CFM, change the plugs, and tune the car again. I had the car running great, however after 50 mi. it started running rough. I took out a plug and the plug was begining to foul. One side of the plug was black and the other was white. I can only figure it is oil, but I can't figure out from where. I figure it could be bad rings, but on all cylinders??? In addition it pulls great with new plugs. My latest guess is that it is either a bad manifold gasket(s) or low spark or both. Any thoughts??

Thanks,

Bryce