Flex Plate Suggestion for 340 w/904

Running a 904 behind a 340 soon. I'm at the point of needing a flexpalte for engine balancing.
I will be using a Hughes 27-30HD convertor. Behind my engine it should provide about 2700 stall. Seems like a flexplate for a 904 is hard to find on Summit or Jegs for a 904 trans thats SFI rated fleaxplate... any recommendations from experience?? seems catalogs only list SFI flexplates for 727. Anyone else running this combo? Thanks.
HR20