I run a heat riser cross-over, stock choke, and pump gas so my problems with percolation seemed unending. All summer long, every time I parked for more than ten minutes. Very irritating indeed!

I tried several things but hood clearance, appearance (sorry but I hate those stacked gaskets), and of course longevity. We drive this car year round in Oregon so maintenance wise it gets treated like any other passenger car.

http://www.summitracing.com/parts/edl-8725/overview/

Paint it black!

As said above the best way to avoid this issue is:

a) Mix in some 110 with the pump swill.
b) Block off the heat-riser cross over.
c) Fuel injection

I just mix in a few gallons of 110 during the extremely hot months and that gets us by.