Joel thanks for the insight on the ignition module. I understand what you are saying but would that stop fuel flow thru the throttle body's jets when moving the throttle level? I may not have been moving the throttle level fast enough to squit fuel but a few others have been around the vette when it did this once before so we may all have moved the level slower, but again not sure.

It may well be a fuel problem...I'm not totally discounting that at all...it just sounds more like an ignition failure. IF the carb was running out of fuel while idling, it wouldn't just shut off quickly...it would stumble for a little bit then die.
You could maybe carry a small bottle of fuel with you...something with a top that would allow you to pull the top of the air cleaner off, and squirt just a bit of fuel into the vent of the carb, then see if it would start right up. If it does, then you need to determine what the heck else in the fuel system needs attention. If it still won't fire off like that, then it points more to the ignition area. BE extremely careful if pouring any fuel into the carb when the engine is hot!!! Don't try to use a soda can or such!

A can of starter fluid in a spray can might be a little bit easier and a lot safer! A fire extinguisher might be needed also! I do like fire though..I had a few take off on me and it was no fun explaining that one..the module does make perfect sense and is very easy and cheap to pop in..
Rich

Joel when it stopped it was not just like the switch being turned off but did sorta just idle down. Before when it happened on the road I had just stopped and fueled up, started and drove off and about 100-200 feet she just die out and I coasted to a safe spot. And had no fuel coming thru jets in the carb then either and had 3 other vette's owner and one of them a good mechanic stop to assist. They felt the fuel pump so I did swap that out as well as doing all the other work to the fuel system to hopefully remove and other problems.

Dan thanks for your offer to have the corvette mechanic see this post, I look forward to hearing his thoughts.

It is entirely possible that the float in the carb has swollen up, and is sticking to the sides of the bowl. The float is made of a resin type material, and they will soak up fuel and expand. New or not, it can happen. You've done so much to the fuel system, that the carb is really the only other thing that could cause a fuel starving issue.
The check valve in the filter can be removed, but I doubt it is the problem...its only purpose is to keep fuel from draining back out of the carb.
Adding the second spacer/insulator under the carb might help, I s'pose, if it is heat related. The Q-jet should have a thick gasket under it. You might want to check and see if your heat riser(on the pass side exhaust) is working properly. If it is stuck closed, it can certainly push more heat thru the bottom of the intake, and thus transfering the heat to the carb...

  I like the heat riser idea..

Well installed second thick spacer today and she ran okay, a couple of short road runs. Then when got back in the garage and shut it down.........antifreeze started out from under engine...but found clamp lose on line from radiatior neck to overflow jug so tigthen it up and hopefully fixed that.

The heat riser I was referring to is in the exhaust, right where the head pipe bolts up to the manifold. On your '81, the heat riser will be vacuum operated, so you should see a small metal tube going down to the riser valve itself. There will only be the one on the pass side exhaust.

 I think what you are describing that you checked is the valves on the bottom of the air cleaner wings/inlets? While those being stuck OPEN would also contribute to excess heat to the carb, I can't see them causing your problem.