You'll definitely get a better
quality paint with the body off, as it is easier to get to all of the areas that need painting with the body up of the ground a bit, as it will be a on a jig. You run the risk of scratching the paint either way, on re-assembly.
Not having primer and color overspray on the rest of the car/frame/engine/etc., is a BIG plus in my book. If the body is currently off the frame, which it sounds like it is, then I would go ahead and have it painted that way. That's just my opinion.
I'm sure there are others.
Congrats on getting closer to the finish line, anyway!
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Joel Adams
C3VR Lifetime Member #56
My Link
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"