This Heavy Duty unit came off a diesel MerCruiser motor. Not sure of the year. Got it in a trade.   The gear ratio is 1:1.51. In examining it I noticed the prop shaft seal (output shaft seal) is in need of replacing. I believe the seal # is 26-821092. The output shaft is approx. 1.18" 

I was going to fix it but no time. The unit turns freely and feels solid. The prop shaft runs straight and true. Splines all look good.  If you are handy change the seal and save money. Sold as is. Fast free shipping.