Wheel fitment question

[Willi2ds]

First off, I just wanted to say hi. and tell you guys how much info I've already got from here in the last week since I bought my 1979 2wd heavy half.

Anyways, my problem is is that I just bought a set of American Racing Nova wheels, they came off of a 72 C-10. The front went on no problem but the rears dont seem to sit flat and the studs are too short, anyone else seem to have this problem? All the info I could find on guys needing longer studs are due to rear discs or spacers? Any help is appreciated.