You can order aset of ohio flattops from Dynagear at (214-631-4677) which are 9 : 1 and with alittle head work you can get close to 10 : 1 , but I wouldn't want more than that as you will have trouble running on pump gas---two of the best items(if it doesn't bust your budget)for your heads is to have stainless valves installed and hardened valve seats , also look at both crane cams website at the "Energizer" series of cams and Comp Cams as well ----they have alot of good choices for your engine!!!!fd :-X11