Head gasket question
 

I’m building a 2.3ss with AA 86mm cylinders and using 1975 911s heads. Based on this would I need to use head gaskets for the earlier (2.2, 2.4) engines that used 84mm pistons, or later because of the 75 2.7L heads?im thinking the smaller ones but thought I’d ask

thank you in advance for any input, probably a basic question but this is my first engine build and I appreciate all of the people that contribute their knowledge on this forum.
Thanks
Nate

2.2/2.4 cylinders have a wide groove and use the fatter ring. 2.7 has a narrower groove. depends on the cylinder.

Hey Nate, not a basic question at all! Since you're using 86mm AA cylinders, you'll want to match the head gaskets (if you're using them at all) to the cylinder size, not the head year. That means going with gaskets designed for 86mm bore, not the earlier 84mm ones. Some builders skip head gaskets entirely and just lap the cylinders to the heads, but if you're using gaskets, make sure they fit the cylinder bore properly to avoid sealing issues. Good luck with the build.

Thanks for the replies. These AA 86mm cylinders use the same head gaskets as an 84mm cylinder, hope it helps someone in the future. Tried them out today, they fit well. I used the Elring brand

The use of Elring vs Victor Rientz is a smart move. There were a batch of VR 2.2/2.4 CE rings that were too large. These thick gaskets often caused a poor torque reading and as they got hot, they would compress causing the heads would start coming loose.

I agree with Henry. I used those 86mm cylinders on my 72 911 and kept blowing head gaskets. Come to find out the cylinder grooves were cut too shallow so the head gaskets would crush and not seat correctly causing blown head gasket. I then changed back to my 84mm Mahle and no problem since!