Need advice on pulley combination

[NVR2L8]

I have done a lot of mods to my '07 GT500 over the winter, including a 10% OD pulley, LT headers, 72mm throttle boby, 65 lb. injectors, 123mm MAF, high flow inlet, etc.

My car currently has a 2.6 upper pulley and a stock SC. A few days ago someone told me that, with the 10% OD pulley, I should go back to the stock upper pulley in order to prevent too many RPMS at the blower. He said the 10% lower and 2.6 upper would turn the blower 19,000 RPMs, which would be too aggressive.

Can some of you "gurus" help me decide what would be the best size upper pulley to go with the 10% OD pulley.

BTW, my car should dyno at a little over 600 RWHP, and my only driving is on road courses. This is a track only car.

Thanks in advance for the help.

 

[racebronco2]

Your pulley combo depends alot on wether you can get your iat2's under control. At 15 psi My iat2's were at 170* and the ecu was pulling 5 degrees of timing. At 12 psi it's more controlled at 140* and only pulling 3 degrees of timing. You will need to find a happy medium between boost and timing retard.