Mercruiser 1.32 ratio behind a 250 hp SBC?

tango13

Petty Officer 3rd Class
Joined
Mar 10, 2015
Messages
75
Hi all,

I was installing new decals on my mercruiser outdrive this spring and noticed a few things that are not adding up:

My outdrive has 1.32 stamped as the ratio, has a "250" hp decal, as serial number reads 4734559 (the 3 might be an 8, not 100% sure).

From what I was reading up online (on SEI's website), the 1.32 ratio only came on 454 applications, and the 250hp merc was only made in 1977 and was a 1.47 ratio.

I'm starting to guess that this outdrive is not the original, as I previously assumed. Im guessing its a donor outdrive that someone slapped a 250hp decal on? The boat is a 1978 so it is possible that it orignally had a 250 setup, but now I'm not even sure whether the engine is a 350 or 305, as it no longer has the decals on the valve covers. Who knows if the engine is even original at this point :wacko:

Is this less common gear ratio going to haunt me down the road?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,585
if your boat is light, it may have a 1.32 ratio.

the old 350's would have been ~250hp at the crank or about 220hp at the prop

early in the MC-1 lineage the 1.32 ratio was also behind ford motors, long before the BBC and the alpha
 
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