Float bowl is stuck, not yet ready to whack it with a rubber or plastic mallet. Info on another forum showed success with Kleenflow. Berryman  is available at a local Autozone and is listed as o ring safe. Any recommendations would be appreciated, TIA.

Proceed with caution. 50 year old carbs are brittle.
Soak it for awhile and pull it out and apply heat with a heat gun or hair dryer. Repeat as necessary. And replace the rubber and brass parts and gaskets while you're in there.
Also I use a # 260 main jet in mine.

And another suggestion. I presoak the gasket and slightly tighten the bowl screws. After a few miles I'll tighten them again. The span across the bowl is pretty wide for 4 screws. Easy to crack the tabs if you overtighten. Keep a rag under it for a few days.

Might be hanging on to the Oring.
Does it move off the gasket but feel rubbery.
Important little Oring 'that one' so replace it regardless.
Normaly it'd shrink & not hold on though so prob not that causing it.

It's on rock solid, no movement at all.

Maybe i'm lucky but i just hit them with a plastic handle screw driver. Yours sounds bad though.

I have gently used a rubber mallet to get them loose. You need to lay it down on something solid, and tap on it on all four sides. Chances are it’s not hung up on the O-ring. Chances are good someone put some sort of adhesive on it. It would be just like hitting yourself on the fingernail or the toenail with a rubber mallet very late blows. 

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Success! Turned carb upside down, sprayed WD40 into the joint, then let it sit for an hour or two. Beat on it some more with a rubber mallet, then was wrestling with it and it popped off. Green nasty stuff inside the carb, off to get some Berryman to soak it in. Thanks to all for the suggestions, project RT3 is unstuck and moving foward