I, too, am going through a '74 144 that I picked up cheap. My '74 has continuous mechancial fuel injection which appears to be pretty simple. I'm in the process of replacing the injector seals which are quite hard from age and heat. I've found the idle to be a little high, and suspect that air may be leaking past the injectors as well as other vacuum lines that have lost their 'elasticity' from long service on the car.

I flushed my BW31 trans, which was very easily done.