I have a transmission from a 66 B-body I’m going to rebuild. I’ve read something about the input shaft being smaller or having less splines, requiring the use of the earlier torque converter?? Did it change in ‘67? I’m not sure can someone shed some light on this??
The '66 should have 19-spline input shaft unless it was converted.
To convert to the later 23-spline you need the inputshaft and matching front pump (and maybe the front drum too if '71+) from a later model vehicle.
When changing pumps, drums and such, you need to verify the input shaft endplay (really a good idea even if re-using the original parts.)
The endplay is adjusted with different thickness washers on the pump.
