Re: Installing a R11 overdrive in my 1948.

Posted by Dave Kenney On 2011/5/16 8:00:14

If you do a fair amount of driving on highways and want better gas mileage (who doesn't?)an overdrive transmission is a very good idea. With a numerically higher differential ratio already in the car you will reduce engine speed by about 35% at any given speed with the trans in overdrive. If you can locate an R-11 unit with transmission from a 1948-1954 Packard doner car with the cable, wiring harnesses, relay, shorter driveshaft, overdrive to crossmember support etc. that would be your best bet. If all you find is the overdrive unit without the necessary extras it will be a far more difficult job to locate the individual pieces but over time can be done. If you use the car for other than city driving it will be worth the time and effort in my opinion. I have R-9 in my '47 Super Clipper and cruising at highway speeds seems effortless. I am sure others with more experience in doing this conversion will chime in.