Being splade they look like they are strong and go into the meat of the rail. One problem with standard 4 bolt caps is you need a T/A, X block, Resto / R3 to use them. One thing I did run into when using a Milodon pan is we had to bulge the pan to fit. with the standard program 4 bolt mains. I would use those caps if I had them. Make sure that you have them installed in a bed mill and then line bore and rehone the cylinders with them torqued and torque plates on both head surfaces .
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