904 identification
1968 or earlier by the single post neutral safety switch.
Good catch!
I'll add:
1.) It appears from your pics that you have mechanical shift linkage. That points to '66 and up. ('65 and earlier were cable-shifted, had a different type of speedo drive, and a ball and trunnion output shaft).
2.) Count the splines on your input shaft. If it's 18 spline, that'll make it a '66-'67. If it's 27 spline, it's a '68 and up. (26 spline would make it a later lockup/OD transmission, but the single post NSS rules that out.)
3.) 18 spline transmissions also had a convertor hub diameter difference from '68 and up transmissions, which means the recess in the rear crank flange also changed diameters. To use an early transmission on a late ('68 and up) motor, you need to have a bushing made to fit the large crank pocket and reduce it to the early size. To run a late trans/convertor on an early motor, you need to have a machine shop enlarge the crank pocket.
