My boat is a 1994 model and came with a 350 MAG and Alpha One Gen 2. I know Merc used 1.47 and 1.50 ratios at some point but I’m not sure which I have as the case isn’t stamped. Anyone know if my era of drive would be 1.47 or 1.50?

It would be a 1.5. And .03 of a revolution doesn't amount to anything.

1.47 to 1.50 = about a 50rpm difference at WOT.