[mattfranklin]

I had a similar issue after parking. I don't drive mine often enough and the pump seems to lose its prime.

1) If I parked nose down on my sloping driveway it seems to be better.
2) If I pop off a fuel hose at the pump and dump some fuel in there before hand it seems to start and run ok.
3) Also, one time I took a big breath and blew hard into the fuel filler (I have unusually large lungs) -- once you've exhausted your air, quickly turn away and move your body away otherwise you'll catch lungs full of nasty gasoline vapor. That helped one time.

EDIT: I have a stock '70 Camaro Z-28 spec AC fuel pump (new 8 years ago) and Holley Truck Avenger (4150-style) 770CFM carb.
EDIT2: For that highway speed problem -- The pickup/sender in the tank has a "sock" like one more filter to catch the big stuff. Replace the pickup/sender to eliminate that potential problem. Also, rubber fuel hose can get old and fat and swell inside. Check the rubber hose elbow between the tank and the steel fuel line under the back of the cab. It might be swelling and choking off full flow.