If car sits more than 3 days, it will not start without being primed first.Can a blown intake manifold gasket cause this.

 

That may be attributed to the gasoline on the market today. It is reformulated and is oxygenated and contains Ethanol all which allows for it to evaporate MUCH quicker than gas used to. If I let my car sit for 3 days or more without starting, the fuel in the carburetor bowl evaporates and when I try to start it has to be cranked and cranked and pumping the throttle until the bowl fills again. I have not found any gasoline that prevents this on the market. EFI cars are not affected as they are a closed, pressurized system not a 'vented' atmospheric system. I don't know if you have other issues contributing to this but that may be all it is.

 

You might also find that your carburetor could use a rebuilding, just a thought. I don't think a faulty intake gasket would cause your problem though.

 

It's probably the well plugs leaking more than evaporation. Give the carb a good rebuild and epoxy or JB Weld those plugs. I usually do the primary ones also just to be sure.

 

X2 - Q-jets have a cast body, and the well plugs are the only place to leak!
Clean well so the epoxy will stick!