This may help (from mmcdetroit.com)
Starters
The factory/ stock classic mopar starters(as seen in the above photo) for 1968-70s era mopars are very heavy and bulky in comparison to today's starters. With this being said when we have not done an OE restoration we have used part number 17466 starters which are smaller and less weight for our big block engines. They even seem to have a stronger start in our experience. I believe this part number might populate a 1994 or so Dodge Ram with a 5.9 v8 engine.
When dealing with the original starters, there were mainly 2 types of starters used from 1962-1987 for the trucks and cars. These were gear reduction type starters.
There was a shorter starter 1.5hp part #2875560 and casting #2875553. A 1.3hp short starter was also used in 1973. Its part # 3656650. In 1973 another short starter was 1.5hp part# 3656575 which was a later production date. The second type of starter was the larger starters which were .5 to and 1 inch longer than the 1.5hp starter. They were 1.8hp and introduced in 1975. These part numbers were #3755250, 4091950, and more.
When dealing with 426 Hemi engines in the 1966-69 with a 4 speed they used direct drive starters.(reference, Finer Points of Mopar E body,
www.mmcdetroit.com)