I've been searching around for a 12 bolt to go into a 1970 Chevelle Malibu, and am aware that the 68-72 are the same. I've managed to come across a 71 monte carlo 12 bolt with 4.10 gears and was wondering if I'd have any problems doing this swap?

I havn't managed to find anything that can confirm or deny this

Welcome to TC.
Monte used the Chevelle rear so it's a direct/bolt in.
You might need a crossover u-joint ,depending on the yoke on the 12 bolt.

Thanks Mike! Greatly appreciate it