[Mr70]

The #738 was used on earlier model Series 10-20 Trucks w/SB.
The #021 cast was originally used on & recommended replacement for M/T equipped vehicles up until 1970,on:
*1970 ALL vehicles w/307cid & 6cyl.
*1969 Passenger 327cid & 350cid.
*1967-69 302cid.
*1964-69 ALL w/230cid & 250cid.
*1964-68 ALL 283cid & 307cid & 327cid.
*1962-69 Chevy II & Chevelle w/HD clutch.
*1963-68 Passenger & Corvette w/283cid & 307cid.

Starters have a part number and date code stamped on the outside of the housing,just below the solenoid.If you relay it,I can check it for you.