What type of stern drive is mine

[kenrahe]

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...

[IMP-ish]

Ken, post a photo.

[kenrahe]

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

[IMP-ish]

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

[kenrahe]

so what would I put in to look for parts

[kenrahe]

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