my ultra has a blue primary spring, 10/M5 weights in it, the secondary is a silver/blue spring with a stock helix which i think is 34 or 36 degrees in the third hole. PSI told me to run 54 gram weights, what do i have? i can't find that # in my book. the sled runs fine, but doesn't really pull all that hard, it engages @ 4600, spins @ 8900 (psi said 8400-8500). it acts like it aint "grabbin gears". if you get it on hard pack it'll eventually shift out. but as of right know my piped xlt will eat it till bout 65mph.