I see nothing wrong with a 904. You can either hog out the one hole for the converter, as the 904 converter has a non symmetrical bolt pattern, or use the older flex plate, if you are not using EFI. The magnum converters are symmetrically drilled. The difference is, that the weights for balancing the assy are on the converter for the 904, and on the later Mag flex plate for Mag engines.