So I was thinking, (oh no Mr. Bill ) the exhaust side of the /4 heads is supposed to be the main weak link when it comes to getting any decent power gains from the type IV motors.....the ratio of what the intake flows compared to the exhaust is too lopsided (the exhaust should flow 75%-80% of the intake or something like that to be ideal?????)
If one was to keep the stock cam (not really keen on splitting the case) and just install a much larger exhaust valve and re-work the exhaust port only, would it make any appreciable difference?? This is for a 1.8 motor with a European racing header.....otherwise all stock...currently D-jet, but that can be changed