Ahhh - I remember those days. Screw driver prying the fly wheel around, starter box wiring smoking. We are so spoilt these days, sort of takes all the fun out of it - NOT
Sounds like Gizz has come up with the hell deal Africa. Go for it mate. Like he said, be patient with the run-in and you will have power to burn. If the carb starts wiggling you can drop a new GX carb in there anytime. I would get a full set of the new nitrile O Rings though. The older chocolate coloured O Rings on the needles and the OR-0004 O Ring under the carb suck. They will dry out then perish and flake, so replace them soon.