Gets hot and stalls out

Have you checked ignition timing yet?

Alternators only put out as much as the electrical system demands. You can run a 200-amp unit but if your electrical accessories only pull 40 amps that's all it'll ever put out. What's the voltage when running?

There is more diagnosis you should be doing with tools instead of "this part might be an issue, replace". All you need to do to check whether it needs a voltage regulator is to use a multimeter and measure the voltage across the battery terminals or from alt output to ground while the engine is running. If it's over 14.5V (ideally lower due to your ambient temps), that's a problem.

If the fuel is indeed boiling, the engine should still at least try to start and run to some degree. If it's not firing at all that points more to ignition issues.