I got into this mess while trying to find pistons for my 153 4 cylinder build. Same combo as a 230. When I threw a 181 Mercruiser crank in the mix the 307 pistons came into play. The stock pistons were .050" down the bore. I got a few sets that should have worked but all came up shorter than expected. That could be the .010 discussed earlier as a rebuilder cushion. The chamfer on some are way more than the valve cuts and are more equal to the dishes. I go a set of tlowe's 250 pistons but still need to get them on the 181 rods so I can measure. Any way I have a couple of sets of rebuilder 307s for cheap.
