I ebay'd a used set of 390 domed pistons & need any specs i can get. Mostly need dome volume and how much lift i can get away with before i have to cut the reliefs. Thanks, i'm new member, 52 yr old drag racer.
What you can do is clay the piston and roll the motor through two turns so that both intake and exhaust valves make an impression in the clay and that will tell you how much clearance there is from the valves to the piston. Depending on how much lift you have now, the measurement in the clay will determine how much more lift you can add.
Yes they're old but in fair shape. Minor pitting and a few dings but the skirts are in good shape. Rings are 1/16" not 5/64" so rings may be a problem. Thanks for the info on the domes. Larger than I guessed. Pistons aren't in a motor so will have to dummy up one in a block with a known lift cam. Thanks for the help. Still having trouble with the computer, got double post and couldn't erase one.
Good luck and keep us posted on the outcome. Nice to see some new members. Those volume specs are from a old TRW catalog. So I'd hope they are correct. You have a few years on me. I was born the same year as the FE.