I want to change my pulley and I want to know if the 3.25 is to small .I have a Thrasher CAI and a 180 thermostat with 1 heat range colder plugsand a reworked exhaust with 2 Flowmasters.Would I be better off with a 3.4 pulley? Any help would be apprecited.
The 3.25 is definately too small. With your mods, I would actually not be suprised to see you getting KR with the 3.4 pulley. 3.4 is definately the smallest I would go with your mods. To go to a 3.25 you would probably need rockers AND headers, or a cam, on top of your existing mods.
Even with rockers or headers, a 3.25 can still cause KR. I wouldn't go below a 3.4. I plan on staying with this pulley even with my ported manifolds. And if I do rockers, I will probably stick with the 3.4 .... maybe a 3.3.
You should definitely stick with the 3.4" until you free up the exhaust a bit more.
With headers, you can go to 3.3" and with Rockers drop to a 3.2".
A cam will allow a drop to 3.0".
Going to a Gen5 Supercharger will allow a .2" drop in size.
An Intercooler will allow a .2" drop in size.
+102 high octane fuel will allow a drop of .1" or .2"
Outside temps below 45*F will also allow a drop of .1"
Beware, these recommendations are generalized.
The only way to know for sure is to scan the car on an accel run to check for knock.