ive got a 36 & 32 tooth pulleys for my 427 Chevy. Does the 36 on top make it under driven????? I,m running a fine line at 9.8 compression, or can i keep the 32 on top?????? thanks Marty

That must be a 1/2" pitch pully, placing the 32 tooth on the blower will give you +12.5%, the 36 on top should be -11.

12.5% overdriven with 9.8 static c.r. will put your effective c.r. through the roof, without calculating it, i'd estimate 14 or 15:1 easily.

__________________
You can't run with the big dogs if you pee pee like a puppy...

Thanks......well that sucks bigtime!!!!!!!!!!!!! My friend Neil races a blown 30 Ford on the Nostalgia circuit. He said big pulley on top for under driven. Now the 36 pulleys centre hole is to big & the 32 pulley centre hole is to small to fit over the belt pulley...........guess theres more machine work to do!!!!!!!!!!! Marty

You could always try an MSD BTM to pull timing out but that's a lot of cylinder pressure for a non-O-ringed block when in boost. I see guys claiming big OD on their street blower motors, and huge boost numbers for turbos on the street, curious how they work out.

__________________
You can't run with the big dogs if you pee pee like a puppy...

Your right about the boost & compression...got no choice i guess! the 36 on top & 32 on the bottom. I never really drive the truck hard anyways....can,t afford broken parts!! Will keep you updated......Thanks