New Member
Jan 14, 2002
I just bought a 98 GTP. I am very happy with it, but I was wondering if I go to a 3.25 s/c pulley what do you recommend as far as other upgrades to avoid getting knock?
I'd go with a colder spark plug (NGK TR-55s), add a trans cooler while you are at it.

Usually with anything less than a 3.4 you are going to need some type of cooling. Several options on this. You could get a Thrasher intercooler (, add water injection (I used an Auqamist 1s but there are other options out there).... May as well get an appropriate sized SC belt too (to prevent slipping).

With a 3.25 and no cooling you will probably get too much knock and not realize the full potential of the mod..

Good luck. :cool:
If you check the board, most people running s/c pulleys smaller than 3.4" have installed an FPR to allow them to manually adjust the fuel pressure to reduce KR.