241 Vs 243
The average I have seen in stock (243) LS6 heads unported from (241) LS1 heads unported with know other change that I have seen out of the cars I have done 3 of them is 15rwhp to 20rwhp and 2/10 in the 1/4 mile. But the results will vary and some tuning because they dont need as much timing in the computer. Its a well worth mod in my opinion especialy if you can buy them used for a good price. That is what I have on my car stock 243 LS6 heads unported just spring changed Comp Cams 921 kit. My car puts down 447rwhp on Mustang dyno. Good Luck on your decision
I see you already have the MS4 in your car, I would stick with it and buy the heads and put them on and take the car and have it tuned but that is just me. The MS4 is a good perfomance cam and is a proven performer.
