Now you're getting there. Vernier Isolastic mounts are adjustable vs. what you have now. They have to be shimmed. Easy to convert the front one that usually needs adjusting more often. Not so easy for the rear. Properly adjusted ISO's make a Commando handle as well as was designed. You've overcome the dated ignition, but may want to convert to electronic eventually. Like your LS, makes starting and running simpler.
Hopefully, you can salvage that carb. Once you're riding and putting it away for the season, you'll need to drain the fuel or there will be corrosion in the bowls and elsewhere. At least your year should have the drain plugs in the bowls.
The '55 is just a memory now, I sold it in '70, joined the Navy to avoid being drafted and bought the '71 Commando while on a cruise in the Mediterranean. So the Chevy did morph into another hot rod. Sure did stop and corner a lot better though.