This is all great info as I have read. Camatv also gave me a lot of insight on the cheetah setups. I got the 421 cheetah pv but still have to get domes cut,cases ported,block ported. I also just got a 10mil cheetah pv that is drag ported by Cameron at redline, but have to get cylinder repaired by millennium. I guess my question is shud I trade my 421 cheetah pv for a 421cub?