My 340 is running hot I think.. I need a sanity check.

I once had a 71 Demon that made a lot of gurgling noises in the heater-core. The hoses were on backwards, and I suppossed that a big bubble of air got trapped inside it. I flipped the hoses around,and all was quiet.This core had 2 same-size pipes on it.Only Mope I ever had that did that.