I just bought a 73 240z with the original engine, with maybe 140k miles on it. The problem is that when I'm gasing it, the engine chokes like it can't breathe. Since the tach does not work I don't know if I'm just redlining it or what, although it doesn't seem like I'm even close to the redline.

I am sorry , you havent given enough information. If you are spinning the engine untill it feel like it is " choking" then 1 you are WAY beyound red line or 2 the engine needs a good tune up. Before you turn the engine into a gernade fix the tach. and take it easy . If the speed- O - meter works shift by that . what speed in what gear ? This will give us a clue. :stupid: