Procharged guys chime in
 

What is the smallets 6-rib pulley you can run on a P-1SC without getting belt slip? I want to get a new pulley and re-tune but not sure how small I can go.

i am at a 3.2 riechard racing pulley right now @ 15psi. your psi will be different though.

I plan to try a 2.9 pulley and see what happens, if it slips then i will put old pulley back on. if i hit near 500rwhp with my intakes here soon i won't try the smaller pulley though.

I'm running a Reichard Racing ultra grip 6 rib 3.4 on a D1SC.

Just get the ultra grip pulley and it should handle almost everything you would want to do on a 6 rib. Unless you're on a built motor that is

Ya believe I either have a 3.4 or a 3.6 right now not sure. I am making about 8-9lbs of boost. Thats with a AFM power pipe, bassani headers, bassani o/r x pipe.

i'd say you could run a 2.9 rr pulley with no slip; but if you are worried about slippage just step up to an 8 rib setup

I plan to step up to a 8 rib but not until later down the road. My plan is to purchase a built engine and then later on jump up to a d1sc 8 rib set up.

From the start I upgraded to an 8rib and no belt slip, only tire slip :D .