Advice on which heads to use. 360 , 302???

The 360 heads will drastically lower your compression ratio if their the older LA type heads. That's not a huge cam so I think the 302's are the way to go. Ports are a little smaller so they will make alot more torque and they have much smaller chambers so they'll make alot more compression. I believe the springs, retainers, and locks should all fit from the 273 heads onto the 302 heads as long as the valve stem diameter is the same and I don't think they changed it. Only problem you might run into is if the springs are dual springs you'll need to have your 302 heads machined to accept them. In stock configuration they only accept single springs properly. Even if they need machined I'd run the 302 heads. The big ports and chambers on the 360 heads will hurt your torque a bunch.