slant six 3sp. to 4 sp. conversion

230 I believe, could be wrong though.
Depends on the year. In the 70s, A230 was the most common, was fitted to either slant 6 or V8 cars. My 73 Duster had the light duty A250 version, labeled in the manuals as "six cylinder only". After the transplant, it lasted several years behind a gently driven V8, finally tossing all the input shaft bearings on the ground in the middle of a nice red puddle.

The 1960s used different numbering, can't recall exactly and my books are all packed in storage right now. But you're not likely to find many 3-speeds left anymore, anyway.

- Erik

64 Valiant, 170 3-spd
82 Volvo wagon, 5.0 5-spd :)