My 360 is overheating.....

Very first thing I would do is disconnect all the radiator and heater hoses and rinse out the block (and heater core since your there)
I remove the thermostat and put a garden hose and a compressor blower nozzle wrapped in a wet towel together in the opening.
Once the water runs in there for a few seconds I hit it with the air to blast it through the block.
8-10 times each direction doing the same with the bottom radiator hose with no thermostat but the housing back on and the hose pointed to direct the crap away from the engine.
If that doesn't do it then start looking at shrouds and a better fan, and if that doesn't do it then a bigger radiator.

A little condensed for content length, but this is the basics and it never fails to find the problem.