Originally Posted by Jethro in Va
That screw looks like the one that holds the rear bushing carrier in place on a 3sp GM transmission.
That could be, but I believe that plug/screw on my tranny is bigger and a hex head. Yep, just checked. 11/16 hex head with .66 dia threads 18 pitch (maybe 3/8-18 National Pipe Straight?) The pin is about .28 dia.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.