There are a couple of adapters available to mate the 700R4, Turbo 350, Turbo 400, etc. to the mid-50's stovebolt sixes. Yes, they're spendy. I believe the late model flex plate is modified with a new center section welded in with the 235/261 bolt pattern. There's also an adapter plate that mates the trans bellhousing to the engine block. If you can find an adapter ring for a Powerglide to a stovebolt six, it would probably be possible to come up with a home-brewed plate to match up the bellhousing bolt pattern. I've got a couple of those Powerglide adapters, BTW. A cast iron PG trans would almost be a bolt-in swap, but the top gear is a 1:1 ratio, no overdrive available before the 700R4 or 2004R (GAG!- - - -PUKE!) vintage transmissions!

I believe Buffalo Enterprises makes a good quality adapter for the OD transmissions to the 235/261 engines.
Jerry


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