I'm trying to find out how GM offered the round pattern and "racetrack" pattern on the NP 205 cases. Were they mixed in over the 70's and 80's or was one used primarily in early production while the other followed later on? Basically, I need to know if any 205 is upgradeable to 32-spline input for the doubler setup. If not, I need to know what to avoid. I have a 205 lined up locally with the 465 adapter still attached that is said to have come out of an early 80's 1-ton that the seller disassembled himself. I haven't seen it yet,but Is this enough to identify wether its 32 or 10-spline? Or does the adapter need to come off to be certain? The potential case would be going behind a TH400 tranny.