Never mind

2021FLTRK said
So I have searched everywhere, and am only seeing spotty information at best. Is anyone running KB399 pistons in a 318? What heads do you have and did you have any clearance issues? I have my block at the machine shop to get it cleaned up, bored and honed. They happen to have a set of KB399 pistons with rings and pins on the shelf from a project that never got used.

UEM Pistons

They will make me a deal on them, but I just want to make sure they will clear the heads adequately. I am running late 70s 360 heads with the 72cc chambers. It is a 1967 block that was just recently pulled out of the original car. The shop measured deck height at 9.59", and said one side is .002" taller than the other. He wanted to take that one down .002 so they match.

Been searching for data. Even spoke to UEM Pistons tech support. Everyone says the "think they should fit". I am paying to have this block bored, decked and the rotating assembly balanced, so I really want to be careful it goes together without having to change it. Any experience would be appreciated.

This is not difficult. Use a vernier caliper to measure from the top of the pin bore to the top of the piston. Then add 1/2 the pin diameter, 1/2 the stroke and the con rod center to center length. That will tell you what you need for deck height. You can get away with +0.005" above the deck and adjust piston to head clearance with gasket thickness. With stock crank and rods and hyper esthetic pistons you can get down safely to 0.030" quench clearance. To keep the pistons from rocking, get Line2Line abradable skirt coating applied. On assembly, the pistons should go in almost snug. Then when you start it and there is no oil on the skirts, the abradable coating wears until oil gets in and it stops wearing. The coating is kind of porous, so it holds oil. This keeps skirt clearance to a minimum and the engine runs quieter due to no piston slap and holds the piston square in the bore.