Call comp tech line and give them your set-up: comp ratio, heads, weight of car, etc.. and they will give you your best options. Go with the bigger head option 210 cc and a 76 cc combustion chamber. If you lower the comp ratio you will have more room for higher boost numbers. Why did u go with a 5/7 rod when you could have gone with the 6 inch rod and had better rod stroke. Are you going to stay hyd roller on the l98?