1970 340 with x heads

it also helps if you know what the early vs later pistons vs aftermarket look like. The early have valve reliefs on one side the later 340 flat tops have them on both sides of piston The old TRW had a dimple for the spark plug etc. Then there is Sealed power and keith black etc. If it is an un molested 70 340 short block it should have the high comp pistons with valve reliefs on one side.