904 and B&M 10235 flexplate

you can file or modify all you want. its still the wrong plate. look at your plate. there are three bolt patterns drilled into it. the large bolt circle is for large bowl 727, then theres a small bolt circle for 727 high stall, and the other bolt circle is for using 7/16 bolts. high stall and later 727 lock-up use the small bolt circle which is the same as 904. this way mopar only had to make two flex plates for all their engines. its the large bolt pattern that screwing up your starter fitment. i dont know if you need the sfi rating, but if b&m dosent make the 904 plate anymore, your going to have to put the small oem plate back on and put the proper weights on the convertor to fix it.