Does your trans look like this one? This is a 1965 B/C body 833 with a 68-69 B-body shifter. I think you can swap out the main shaft for an a-body one and get the correct the tali shaft housing to make it a slip yoke, guts and gear set are pretty much the same, and yes there were iron tail shaft housings for a-body cars. I’m sure someone will chime in with more info.
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