Hey guys ive got a mustang with the smog pump removed and they never plugged the holes in the back of the heads. They are AFR 185's. The left rear head hole seems larger than the right rear hole. What are the thread size/pitch of those holes?
Thanks a lot! I do remember those, but I have Trickflow heads so i didnt know if AFR used the same thing. my guess is that they got one insert in the left head and forgot the right head maybe, because they are clearly 2 different sizes right now. Seems like i tried a 5/8" bolt in the right head and it wouldnt go it, but i will try it again.