Can’t remember part #s but when I bought my b+m hole shoot for my 74 360 727 combo the converter was made to fit all engines external and internal the flex plate had the counter weight on it. Recently bought a forged steel rotating assembly from scat cranks with internal balance took flex plate to machine shop and had them machine counter off. No problems to date every runs nice and smooth.
I don’t think Chrysler built a 360 with internally balanced crank look at harmonic balancer if it has the counter weight in it its external balance your stock converter should have a weight on it as well.
