I posted this as an email but I also wanted to list it here just in case some of us don't read the emails and also good topic to look back on.

I just purchased a motor 1972 400 with 7J2 heads. The motor is supposedly rebuilt time will tell. I do have plans to tear it down and verify.

My question the valves are 1.94/1.66 96 cc. The published rated HP is 200.



Now I looked at a 1971 with 99 heads valves are same but 98 cc. This motor is rated at 265 HP

A 1970 with #11 heads has the same valves but 80 cc.. This motor is rated at 265 HP.

Maybe some one can explain the big difference. Could the cams make that big of a difference?



Now one more question would it be worth the increased hp to change the heads out and if so which heads would I go with.

A little history I already have a built 455 4 speed 69 coupe. I am running 6x 4 heads and this car flies. I am not looking for the same power but I want more then my 350 is putting out.