The bellhousing is the key piece, no reason not to stay with your 53 bell, it accepts any pre63 inline and also the later trans. Sounds like you have it figured out. Now the 57 clutch may not fit into your old bellhousing, you'll have to check this out and you could stay with the 53 stuff.
My set up in the 46 pickup: 1961 261ci with original 46 bell(adaptor plate to trans)(OLD 40s/early 50s 11"truck clutch & disc), to T-5 trans, to open drive. You won't need the adaptor for 53.
Best of luck
