help Identify upper unit gear set, Mercruiser MC-1 (Early)

I have a sterndrive unit with bad upper gears... the serial number on the tag is not legible and I dont know any other way to identify what unit it is, but it is one of the models before the alpha was introduced.... (it has the little lifting eye built into upper gearcase cover)

I have the gears out of it on the bench....
so I bought used unit that looked identical to get the gears out of, which are in great condition, but what I find out is that the lower unit drive shaft that sticks up in to the upper unit is an 8 spline on mine, but a 13 spline on the donor unit.... so the gears are not compatible....

they ARE the same ratio (1.98 for 4cyl engine) but the gear length (the skirt? that has the splines inside of it) is an inch longer on mine than on the donor gear...
the lower unit input shaft is an inch shorter on my lower unit than the donor unit...
also, the small upper bearing (that rests in the upper unit cover) is pressed on the gearshaft in the donor unit, but my unit has a retainer nut holding it on the shaft.. the upper part of the gearshaft appears to be the same length (except for the additional length for the nut holding the bearing on)

so I need a gear set 20-24 tooth with the shorter 24T gear.... does anyone have a part number for the gearset I need? (I can find no reference to the gear sets being different in these early units, other than the ratios)

if it helps any, the first four numbers on my unit are are 2649???
and the ser# on the donor unit is 3132461, but it has the wrong style of gears... thanks for any help you can give.

here is a photo of the gears... I need the gear-set that has a driven gear that is the style of the one on the left.... the gear on the right is for a little later model drive...

You probably wont find an 8 spline gear , your best bet is to use a newer MC1 or Alpha 1 complete drive. Considering yours suffered a oil loss/low oil failure the bearings all need replacement and the tools to shim it properly
Could get a whole new drive with a 3 year warranty SEI "sterndrive.cc"
SE104 , short yoke

I have a good 2.00:1 Alpha drive for sale.

It's a 1.84:1 upper with the high altitude lower, came from Lake Meade.
700+shipping.

Some twenty years ago my neighbor's friend let his 60's era 120 engine freeze. They did a complete re-power and I bought the old engine and drive for parts. Left over is the "leg" {unmolested). I will be in Banks, Oregon on the 13th of August. Meet me there with two six packs of Widmer's Hefe and it can be yours.

mcomm said:

Some twenty years ago my neighbor's friend let his 60's era 120 engine freeze. They did a complete re-power and I bought the old engine and drive for parts. Left over is the "leg" {unmolested). I will be in Banks, Oregon on the 13th of August. Meet me there with two six packs of Widmer's Hefe and it can be yours.

Click to expand...

I will be there.... the price is VERY right! thanks...

Bt Doctur said:

You probably wont find an 8 spline gear , your best bet is to use a newer MC1 or Alpha 1 complete drive. Considering yours suffered a oil loss/low oil failure the bearings all need replacement and the tools to shim it properly
Could get a whole new drive with a 3 year warranty SEI "sterndrive.cc"
SE104 , short yoke

Click to expand...

even though the old 8spline gears are no longer available, does anyone have the original part number for them?... it would sure help me search for a set.

I have just finished doing a full inspection and resealing of the lower and would like to use it, but i need set of gears or a matching upper... MCOMM has a complete that I will hopefully get, but I would still like to repair this perfectly good freshwater leg that has bad gears in it.... the bearings are the cheap part, as they are common and readily available at the bearing house...