I am missing 300 rpm compared to my last 2 850 s that i had set up the same as this one. I found a set of filter socks at a local dealer in my area so I can rule that out. Sled was a rental with 380 miles on it, so I guess Iwill check the compression and clean the exhaust valves. 10-68s, stock helix, Zrp back shift brg, SLP 120-340 pri spring, 47c gates belt (also tried a good polaris belt it only gained me 100 rpm more)