!!!! WAIT A MINUTE !!!!

Let's get this STRAIGHT!!!!

You are saying??

That there is a GEAR on the crank, and a GEAR on the cam, and NOTHING ELSE, no chain, no idler gears, etc?

THIS MEANS one of two things:

Either this is a reverse rotation marine engine

or

It's a normal rotation engine with a gear drive cam.

IF THIS IS TRUE you MAY NOT be able to use a standard distributor unless the dist. drive gear on the cam / driveshaft was ground 'reverse' to compensate.

YOU CAN EASILY tell if the distributor is "standard" CCW rotation for a BB / RB. Simply "spring" the mechanical advance. Easy---if the dist. is CCW rotation, you must "spring against the spring" CCW, and the spring will "pop back" CW

You can tell if the engine is reverse rotation by rotating it with a wrench and examining how the valve train operates.

If you have the starter, hook it to a battery and see which way it operates, then visualise it operating the flywheel. ---- OR --- "hand rotate" the starter drive to see which way it ratchets. (over runs). The starter obviously operates the other direction.

To put it differently, visualise the starter, as if you were viewing it installed, from the front of an engine. Visualize that as an engine starts (normal rotation) the flywheel rotates CW as viewed from the front. This means that the starter drive gear will be rotating CCW AND WILL RATCHET in that direction.

The chances of this being a "basackwards" engine is slim, but they do exist