1956 merc rear end housing

[kickinchickin]

Any recommends for rebuilding or replacing rear end in a '56 merc Montclair have replaced the 312/mercomatic with a 390/c4, I believe I have the Dana non positraction underneath now, seems alright but will it hold up under a little abuse? What are the options: on 9", custom built curry looks expensive, not sure if '57-'59 ford is to wide 1966 mustang supposedly about the same anyone replaced theirs? Thanks, David

 

[miker98038]

Kind of depends on which axles the Merc used, they varied in diameter between ford cars and trucks, and I don't know what merc's used. But the Dana 44 gear sets held up in Corvettes and early Vipers. I have changed gear sets 3 times, and added posi (different motors and transmissions. The gears never failed). So, for me, a 9" would have been cheaper in the long run. If you don't need posi, and the ratios right, just run it. You'll work hard to break it.

 

[Lanny]

Your stock Merc rear end has 5 lug 5" bolt pattern, so if you use a '57-'59 Ford or
a 1st generation Mustang, they all have 5 lug 4.5" bolt pattern, so if you want
to keep the same bolt pattern as your front has, you will have to have the 5" bolt
pattern drilled into the axles and drums.

The '57-'59 Ford car and early Mustang rear ends are about 57" axle flange to flange
so measure your rear and see if the measurement is close.










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[Dobie Gillis]

Are you sure it isn't a Dana 45? I have a '55 Merc with the 45 from the factory. It's essentially a truck axle, was used in some Chebby pickups. It should hold up to at least a mild 390 no sweat. Internal parts are hard to find but most 44 parts will work with some creativity.