Alright I made a test rig out of a Honda GX200 engine to test the alternator.
It provides about 100 amps of very easy to weld with DC power.
My modified alternator with new slip ring, brush set and 250 amp stator.
This is the final configuration I am going to use with the big engine.
Big rectifier, with bigger heat sink for welding and recharging batteries. It will get a fan in its final configuration but other wise will be used as is.