Originally Posted by turtle64b

Interesting...

Thanks for the info!!!

I'm not sure my tranny is ready for that much boost haha. Or me ready to spin the Vortech bearings that fast haha. But since I'm swapping out the pulleys anyways, I might go with the 3.15 jackshaft and maybe the 3.0 SC...

Per the Vortech calculator, I'm at 55.6k RPM now (with the serp-side 9lb pulley). Bumping down to the 3.0 while keeping the 3.15 ~stock size jackshaft would put me at ~58.4. Strongly debating stepping down the size since it'll keep me in the limits of the tranny.

If I had the 928 Supervortech upgrade, I'd go 3.47 jackshaft and 2.85 SC, which would spin it ~68k!

Did you just source the longer bolt from Lowe's or similar? Did you increase the SC-side idler?

Thanks again!!