Went and helped one of my friends in the hot rod club sort his 350ci Chevy motor, he had fitted new alloy heads with roller rockers and it was running like a pig, Went back to basics, reset the valve lash (hydraulic lifters) correctly, set ign timing by ear and sorted his carb. Running on 8 now, think it needs some HT leads as a bit of random miss on idle but it reved clean in his garage.