What type of stern drive is mine

The only numbers I have are Transom #OB853830 Drive unit # OC348383 on one stern drive the other one's number is OB865683 are these alpha 1's if not what are they and are there parts interchangable...

 

Ken, post a photo.

 

here's a pic

First pic is of the one I want to switch for the next if those don't show up to good i'll take better pic's tomorrow as my garage is not that well lit for night pic's

 

The upper unit top cap with the swept lift ring and the trim cylinders are pre-alpha.

"Mercruiser produced several models of sterndrives before the Alpha One was introduced.
The common "R" sterndrive, 888 sterndrive, 898 sterndrive, I and MR as well as others.
Changes included cutting lower gears at an opposite angle and changing bearing load design on lower drivehshaft. This allowed for a much more stable pinion gear clearance for added strength. Almost every pre-alpha part can be ordered from the Alpha One Parts section.
Pay attention to R or MR specification in the Lookup Index."

http://www.sterndrives.com/mercruiserhelp.html and http://www.sterndrives.com/pre-alphaparts.html

 

so what would I put in to look for parts

 

Thanks imp also the help site you sent me has great info thanks AGAIN