The flywheel tooth count is dependent on the bell housing, not the starter. So if you accidentally installed a 157t flywheel in a bell housing meant for a 164t no starter would mesh correctly.
Are you buying the starter at a parts store, or junkyard? Just make sure the starter is not one of the 3-bolt style. I've heard that even they can be bolted up, but I thought the boss/flange for the 3rd bolt was in the way and might interfere with something.
Could have that wrong, but it's still worth noting. There are plenty of other gear reduction starters out there that don't have the 3rd bolt that you're not limited to just that one style.
Paul