Thanks for the responses guys. First let me say that I wouldn't be butchering some beauty of a 142s. I got the car in a terrible state off ebay for $400 and built it for a racing series called 24 Hours of Lemons, so it was already beat up. After the first race the rest of the team bailed on me and so it has sat in my garage for 2 years now gathering dust. I promised a guy he could have the car and he is supposed to pick it up this weekend. Out of curiosity I was checking out the rear axle when I was getting it ready for him and realized how well it would work out for the Datsun. So if he doesn't show up (as he is rather flaky) I will be keeping it for the rear axle. Then I'll part out the rest and trash the chassis/roll cage.

Yeah it has a Dana 30 ddgonzal. I believe there are size differences of the diff between the 140 series and the 240 series. I'm not sure if that will limit whether I can go LSD or not. And yes D, I am looking to do an engine swap once I have a rear axle figured out. If I can do this then I'd be looking at ~200hp for a start to see how things go. If the Volvo gets picked up by this guy I know someone local with an 81 Datsun 510 Wagon they are trying to get rid of. It has the L20B and 5 speed so I would take those and the rear axle from it and bring it all over to the Datsun for a lower HP build.

Thanks for the heads up Rallytwit re: the springs. It seemed like most axle upgrades require this modification either due to coil springs or the leafs being unaligned so it doesn't concern me too much. I just need to do some research and find a shop I can trust to do it right.

And I have been wavering lately. I'm debating the rally route now...I'm finding out the rallycross scene here has shrunk like crazy since I was last taking part in it and that would be my main use. Not sure...would have to figure out what exactly to do with it then.

If I still have the Volvo next week I'll get the axles off for comparisons and post it, maybe it'll be useful info for the wiki on rear swaps haha!