Re: [OMC-Boats] Newer Upper gear cases

From: BC Howk <bchowk@...>
Date: Fri, 14 Aug 2009 17:35:26 -0500 (CDT)


I'll have to give them a call, I'm not seeing anything older than 73 in there. Thanks for the link...

I just got it in my head that I might look into a rebuild of my upper unit and while at it remembered your site had info on the ratios. so I should have a 25/25 with a 15.23 lower unit to start, the next step is the 21/19 with a 15.23 lower for the 165 hp I-6 (I think this is the territory I need to be in) changes the final ratio from 1.54 to 1.39 the least drastic step to take unless I can use 70's gearing to get my upper ratio to 21/ this point is a bit of an intellectual excersize and trying to figure out what my options are.

I'll check in with the group again once I nail down the plan.

Thanks folks,

On Aug 14, 2009, Lee K. Shuster (lib1) <lib1@...> wrote:

Go online and look thru the GLM catalog or call their office for advice. They have a fairly extensive listing of upper gear sets by year and hp rating. I'm pretty sure you can interchange the upper gear sets and housing to/from electric shifts: 69-71, 72-78, and the later cable-shifter 79-85 stringers, at least that's what I conclude from a quick glance at their catalog.
I would imagine you would be looking for the 21-19, 21-18, and 21-17 "in-betweener" ratios.  The 21-16 is the tallest from the Chevy and Ford 351, while your Buick's present ratio is very close to 1:1, either 25:25 or 21:20.  If you go used -- then you want to look for upper gear sets from 165, 175, 190 hp stringers (ie Chevy I-6, and 302 Fords which are pretty common.)
----- Original Message -----
From: BC Howk
To: omc-boats@...
Sent: Friday, August 14, 2009 1:58 PM
Subject: [OMC-Boats] Newer Upper gear cases

Does anyone out there know what the difference is on the upper gearcase for a stringer post 1977.

I've been toying with the idea of changing the gearing on my sportsman and an upper gear case caught my eye on ebay relatively inexpensive (comparable to just gear sets I have seen) rebuilt with a nice 21-20 gear ratio but it says it is for an 82-86 3.8 liter V-6...OK, I have not dug really deep into my outdrive research...yet, but I haven't seen anything that explains the diference and  I am just curious if I could use this newer upper gearcase and bolt it right in, I mean judging from every picture I have ever seen the difference is not immediately obvious...

Anyone know? 


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