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I have a 51 200 with overdrive. The stock 288 has been converted to a 327 compliments of a donor engine, bored out to .080 with a mild street cam, so it has sufficient pep. The shop manual says the overdrive unit came stock with a 4.1 to 1 rear end, and the ultramatic with a 3.9 to 1. The local wrecking yard has 55 Clipper with an ultramatic. Does anyone know if the 55 rear end will swap into the 51 without much trouble? And if so, does it allow the engine to cruise at a lower rpm?

Only challenge there is that the brakes\drums are different. Not sure if the larger 51 backing plates, and drums are a match for the 54/55 style axles where the drums, brakes and bolt pattern are smaller.

David, does the 55 Clipper have TL? If so, it probably will not work. If conventional leaf springs, then maybe. Another consideration is the rear u-joint. Also, I believe the ratio for the TU equipped 55 Clippers was 3.54:1. 3.9:1 was the ratio for the manual shift transmissions and those with OD.

(o[]o)

This may be a great questions for Ross Miller as he would know what can fit what.

I'll go check the Clipper out and measure the hubs. I think it has the traditional shock/spring setup instead of the torsion bar.

The 55 Clipper rear is an odd duck in that it has the large pumpkin of the 53-54 cars, yet used the small axles and wheel bearings of the pre-53 cars. Thus it will bolt into your car if you use your backing plates and drums. You might need to shorten the driveshaft a bit, and you will need the hard-to-find stickshift yoke to install on the pumpkin.

Your car pulls the equivalent of 2.95 axle when in overdrive so I am flumoxed as to why you want to change the rear. All your performance gains will be as nothing and the car will be bothersome to launch if you use a 3.23 rear. The ratio in overdrive will be 2.32 which will require frequent kickdown.

I built a replica of Cecil Hayes AAA sanctioned stock car for a dear friend some years ago. (53 Clipper Deluxe club sedan, now in Warren) The engine was pretty much as you described and we ran the stock 4.10 with overdrive. The old girl would break loose in first gear even after she was already rolling if stepped upon. I hardly ever drove it over 90 but the engine didn't seem taxed by the revs.

thanks guys. I guess I can quit worrying about that issue.