What is This Outdrive?

[76SeaRay]

Picked up a Mercruiser outdrive at auction for next to nothing but need help identifying it so I can rebuild it, particularly the lower unit.

The serial numbers are barely readable without guessing. Transom mount serial number appears to be 6868702 and the upper unit appears to be 6908762. These say it is a 1985. The lower unit does seem to have a serial number anywhere. So, trying to determine if this is an R, MR, MC1, or Alpha One and gear ratio. Planning to put it behind a 5.7L GM engine not greater than 300hp.

Unable to upload pictures right now. Will try that later.

 

[Davetowz]

In the I/O faq

 

[thumpar]

You will need to figure out the ratio. If it is wrong it will cost you more to change the ratio than finding another drive.

 

[Fun Times]

6868702 would make it an 1985 Transom Model number 00011005.

And if the serial number 6908762 is correct which it looks like it may be then it should be 1.50:1 G.R which works on V8's.

1985

MR

Model number 01508015

R/MR ALPHA ONE STERNDRIVE

 

[76SeaRay]

Thanks, trying to upload pics again... No luck, getting an Unknown Error everytime I try...

 

[76SeaRay]

So, if I understand this correctly, it is an Alpha One MR... I have had trouble sorting out what the difference is between MC-1, R, MR, and Alpha One. Based upon the Mercruiser info in the sticky, the MC-1 is Pre-Alpha only. Then R and MR are versions of the Alpha One correct? One of the places I tried with the serial number said 1985 but under the column hp it had an MC1...