What compression have you with RKT head??? and what difference between stock_RKT?http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/confused.gif

Around 150 or so. It all depends on what Kelsie designed it for. That's the beauty of his heads. You can decide how much compression and what fuel you want to run. The real advantage in his heads is in the design of the combustion chamber, not the increased compression.

You'll find a wide variance in stock compression depending on altitude. Kelsie's head can be designed to give whatever compression you want at whatever altitude.