anyone give me a pointer? here goes, fuelling is spot on, drives lovely through the range and comes on boost strongly. however when under extreme load, too high a gear and letting the engine pull through to higher revs i get a loud backfire. did this at 15psi, since knocked it back to 12psi. its only when the ignition is under heavy load. new plugs, fuelling setup and timing is spot on. im guessing its eith dizzy,coil,leads or poss plug related. its not boost cut as it peaks/holds waay over 10psi without issue when not labouring the engine. cheers folks

also rev counter either wont work or works but not accurately.