i have an 88 745 turbo that has a fuel issue, not getting any. and i have a chance to buy a runing 90 744 turbo for a song. both are manual trans. as far as fuel pumps go, are they interchangeable? and what other issues might i run into purchasing this 4 door sedan as a parts car?

 

Well, I had an 84 760T and still have a 90 740, so I can speak to this with some knowledge.
Obviously, the front wings are different...but that's the most obvious difference. Turbo Volvos went to LH2.4 fuel injection in 1990 so that means the crank signal is from the flywheel rather than the Hall sensor in the distributor in the 88. So...both dizzies look the same but are not. The fuel pumps are identical. The ecu and icu are different as are the AMMs. Both are 95% interchangeable. If you have a specific question, just ask...either here or drop me a PM. There are some things on that 1990 model that are easily sold if not needed and in good condition. Body wise, there were a few things specific to 90 that changed for 91+ cars. Specifically, the hood, grill and "L" trims between the grill and headlights. Also, as the 90 is an LH2.4 with a flywheel with sensor dimples for the crank sensor, it will bring an easy $100 just by itself. The older LH2.2 flywheels not so much.