Originally Posted by T-bucket23
You need to supply a lot more information if you want help
to start with
Cam model or specs
Ignition type and timing
Head type (model)
There are people here who can help but they need info.
he bought it from a guy so I dont think he will have the specs. It doesnt sound like he gave him any info on it. I dont buy used motors especially blower motors from people. Unless you plan on tearing it down and rebuilding it. Just to much to risk. the teeth like eric said is the best way. I am not sure on the exact math but there are people here who can tell ya. If it were me I would just buy a few different pulleys and play with it. I think you can even buy them in sets.
but remember the higher the boost the higher your comp ratio will be so you depending on how high you plan on going you might have to run higher octane. have fun though. and good luck