What mods for my 904 when using the BPE 408?

One thing not often mentioned about flex plates is the fact that the B&M flex plate (or other race HD style) is a much thicker and more rigid type vs. the oem style that actually flexes. It’s less forgiving/ doesn’t really flex compared to the oem. If the block has ever been line bored you might run into a scenario where the crank is on a different centerline than the trans input shaft and pump hub bushing etc and the converter being on a less flexing plate could wear the bushing in the pump, possibly more so than using oem. Just something to consider when deciding going with an oem or more race oriented piece that would require checking things and possibly using offset dowels on the block.