stater motors?

[Denee007]

Howdy and Goodmorning!
I'm trying to figure out which starter motor to put on my engine. The engine came out of a 72 Impala. The starter that was on it did work. I don't know how old it is/was. I thought about putting in back in, but would hate to have to pull it back down if it was shortlived!

I was looking at the mini starters, but unsure of which/what to buy. Plus one for sale on Ebay/Eastwood asked for which flywheel, a 153 tooth or 168 tooth, but I didn't count the teeth on the flywheel! Is there a way to tell which flywheel I have without counting the teeth on it? It does have an automatic th350 transmission.
dne' ; )