I know you can swap the early ALU case TF input shaft/pump assembly with later ones to open up TC options, but can you swap a later pump into the 61 TF and allow a later TC/flexplate and crank setup?

Dunno.

MIght be simpler to swap a newer TF in as well and used Imperial Services kit to still allow the pushbuttons to work http://imperialservices.net/Cparts.html bottom of page.

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