200R4 update
No problems asking here. I relates to the thread and may help someone else looking to do the swap. There are threads you can search for about flexplate issues. Otherwise, Summit has them, Art Carr has them, or you can get a weighted converter. I bought my original non weighted stall converter from a local converter source pretty cheaply. I got my 200R4 converter right from Art Carr. The way the flex plate worked on my motor was a cross shaped piece bolted to the motor and the flexplate bolted to that. If I was in your shoes I would call Summit or B&M and tell them what I am doing and ask them what you need.