try weld talk
I have an old miller spool gun that I wanted to use on my lincoln SP 200 commercial size wire feed for welding aluminum faster than Tig. I signed up for the Weld Talk Forum. Some of the service tech's and welding engineers are on weld forums. You might get a better answer from a Pro there .The answer there was to just buy a $ 1200 power pack to run the spool gun. I wanted to find out if the lincoln would make it work. Spool guns are a lot cheaper now, I might look at a lincoln for mine and sell the old Miller.