Gear Ratios

yjanray

Petty Officer 1st Class
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Jul 30, 2009
Messages
257
So I am thinking of getting a new outdrive. My ratio is listed on the housing as 1.65R. I am looking at a new to me out drive that says it is 1.62 and has a 24/24 tooth count. How do I make sure that unit will mount up to my transom with no issues.

Thanks!
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,344
As long as its a Alpha 1 drive it will bolt up . a Alpha 1 GEN II drive will not. Alpha 1 5 nuts and a allen under the zinc, Alpha GEN II 2 nut has nuts and bolts on the sides
 

yjanray

Petty Officer 1st Class
Joined
Jul 30, 2009
Messages
257
As long as its a Alpha 1 drive it will bolt up . a Alpha 1 GEN II drive will not. Alpha 1 5 nuts and a allen under the zinc, Alpha GEN II 2 nut has nuts and bolts on the sides
The one I'm looking at is a older MC1 drive that was recently serviced and never put back on project boat. It says It has a 1.62 gear ratio but my current drive is 1.65R. Will it work with my motor?
 

alldodge

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Mar 8, 2009
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42,543
The one I'm looking at is a older MC1 drive that was recently serviced and never put back on project boat. It says It has a 1.62 gear ratio but my current drive is 1.65R. Will it work with my motor?

Should bolt right up an not be an issue
 

kenny nunez

Captain
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Jun 20, 2017
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3,327
The 1.62 was designed for the 470 engines, however if a boat was to be used at a high altitude then the 1.65 was recommended.
 

Bondo

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Apr 17, 2002
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71,082
Ayuh,..... 1.62:1, 'n 1.65:1 are virtually the exact same ratio,....

Swappin' a drive to yer I6, you'll need the shorter input shaft, vs: the normal longer shaft used on motors other than the In-line GM motors, durin' the MC-1 years,....

'n I believe the 470s used either a 1.65:1 for lighter hulls, 'n the 1.84:1 for heavy hulls or higher altitudes,...
 

yjanray

Petty Officer 1st Class
Joined
Jul 30, 2009
Messages
257
Ayuh,..... 1.62:1, 'n 1.65:1 are virtually the exact same ratio,....

Swappin' a drive to yer I6, you'll need the shorter input shaft, vs: the normal longer shaft used on motors other than the In-line GM motors, durin' the MC-1 years,....

'n I believe the 470s used either a 1.65:1 for lighter hulls, 'n the 1.84:1 for heavy hulls or higher altitudes,...

Can I take the input shaft off of my upper and put it on the new one in an getting?
 
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