Hello,

My name is David and I have had my '64 122 for a year now, my first car. My father has been driving his 144 since 1971 (bought after someone hit his '68 and the safety impressed him) and keeps his '62 P-1800 in the garage, so I of course had to get an Amazon (I love it!). I've taken care of EVERYTHING except an overdrive. I can get one, and it's the later one (I know not to use the M-41A, my father's experience from years before I was born). My question is: How much I need to get cut off of my driveshaft to be able to fit an M-41 in place of my M-40. If anyone has done this before and could tell me his or her story, I'd greatly appreciate it. Also, any tips on the solanoid (?) and does anyone know whether I absolutely MUST get a shorter rear end to use the overdrive or will my engine not propel the car when I engage it with the stock, 4-speed transmission?

Any help at all is appreciated,
Thanks for reading

 

Don't know if you got your questions answered, but one has to look at the transmission's final drive ratio to evaluate this matter....and also, where one will be driving.

Most all transmissions of those years had a 1:1 final drive, and an overdrive transmission was around 1:0.70 ratio. There are tire/transmission calculators on internet, but you can also, sometimes, change your tire size to compensate for rear-end gears. Here is one,

http://www.ajdesigner.com/phpgear/ge...n_velocity.php

but I know of a better one, if asked.

Normally, a 1:1 transmission will be mated with a rear-end that has a "taller gear."

If your rear end has tall gears, your engine peak performance will be off.