Originally Posted by Bonneville92V688
EEK. Well, you better get a stock pulley on there, or do the proper mods needed to run that pulley. You are probably killing your engine with KR (knock retard).
I'm not even sure you can run a 3.4/3.5 with a tensioner pulley change. (I'm not sure on that, I own a Series I.)
EDIT - You did measure the pulley across the belt ridges, right?
You do not need to change the tensioner with a 3.4", if he went below that, yes.
If he'* running a 3.5" he should be OK with a FWI or CIA. Shoudl put in a 180 thermastat though. If it'* a 3.4" Ya, that'* to much.