I recently did a run using Project 64 and i'm wondering, can I still submit the run?

PJ1.6 and 1.7 are common to allow, anything over 2.0 is banned (usually). But, like Yoni said, it’s game by game and they’ll usually specify in the rules if it’s allowed.

Just because it's banned on the leaderboards doesn't mean you can't use it. Don't let the regulations deter you from enjoying your gaming! I practice a lot with carts and emulators. When it's time to make a run for the leaderboards, just make sure you're within regulation.