Here is the situation....I was out for a cruise and came upon a nice straight away took her up to about 90 for maybe 5 miles everything running and handling just fine. Then had to come to a stop at the entrace ramp of highway due to construction. I jumped out into the traffic and tried to give it a little kick to get up to highway speed and it just fell on its face as if the fuel had been cut off. I backed off and eased it up to speed with no problem, but if I had needed to jump on it I would have been up a creek. It has done this once before and I tried to repeat today. Got it up to operating temp, came to a stop and kicked it and ran great. Anyone have any ideas...Oh the carb has been rebuilt in last 6 months.

 could be fuel filter, maybe media colapsing, do you have a new accelerator pump diaphram in the carb,,could have a pinhole in it,,rd

carb totally rebuilt and fuel pump replaced last 6 months

First thought is the sock filter on the end of the fuel pick-up tube in the tank.
Second thought is possibly the HEI module...

If you can drive 90 for five miles, it probably is not a fuel supply issue, unless it is something weird like a flap of dirt sometimes blocking flow.  So Joel's suggestion of the HEI module, or coil, etc, seems more likely.  It would fail under the heavy load of hard acceleration, but work (for a while) under lighter load.  And it would more likely happen after heat had thoroughly soaked into everything.

Good luck
Larry

I wouldn't lean towards the sock or pump if it is a intermittent problem.

It doesn't make sense that it is associated with heat (up to temp) if you drove 90 for 5 miles it was up to temp.

It sounds more like crap braking loose when the secondaries open or a float level issue starving the beast for fuel.

Good point Gene.... Obvious and cheap is always the best path to venture down 1st!