I have a 327 chevy engine from a 65 chevy supersport that is mostly stock except I'm running duel quads. The intake is a old edelbrock with 2 390 Holly cfm carbs. Problem is the intake was warped or so I think as the engine surged at different speeds and ran rough. I put a straight edge on and saw that there was enough light for a piece of paper to push thru. I took the intake down to a machine shop and they milled .003 off. I put it back on using Fel pro gaskets and it still is running about the same. I sprayed water along the intake to see if there was any change and it ran really rough for a few seconds. Torqued the intake to 15 lbs for a good seal which is probably a little too much. I know the problem is with the intake as the origional 4 barrel ran great and the 390 carbs are good with a total rebuild and are synchronized. Can't think what else I can do.