St 400
I did some research and found out the following:
(1) Indeed, the Super Turbine 400 that replaced the Dynaflow for 1964 will bolt to the earlier nailheads ('57-64 364/401/425) but not the early 264/322.
(2) However, the crankshaft was changed to accommodate the ST 400, as was the flexplate; but all is not lost! There are a couple of people/companies selling a bushing to adapt the crank pilot to fit the "normal" torque converter of the ST400 (switch pitch or not) and it is possible to modify the 64-66 flexplate to fit the larger crank register of the 57-63 crankshaft. Oh, and some say you can change crankshafts, but they forget that the 364 has a shorter stroke than the 401/425, but the 364 was not offered after 1961.
(3) A small modification is also necessary, apparently, to limit the stroke of the starter bendix so that it does not get stuck behind the flywheel.
(4) General Motors continued to manufacture and sell [as a "universal transmission"] the nailhead bolt pattern Turbo 400 after 1966! Turns out that the nailhead transmission has a shallow bellhousing that leaves room for adapter plates. And which vehicles would have these? You guessed it -- JEEP! all the way through 1973 according to some sources. So these nailhead turbo 400s are not quite as rare as some would think.
As for the transmission I have, and Pete's engine - we would need a nailhead flexplate and a conversion bushing. One company sells both as a package for $295 - seems pricey considering flexplates are generally under $50 for popular engines, and another company lists a bushing for $50. I will do some more searching for sources for stock replacement flexplates.
440shorty
BTW - I can rebuild the Dynaflow, but converting it to an open driveshaft would be another matter...
