I recently bought a 2101 edelbrock intake manifold. there are two threaded holes on the manifold next to where the thermostat and water neck go. one of them is for the heater hose and the other one i dont know what it goes to. I was just going to plug it up but i would like to know what it is for first.http://sigs.flybynightops.net/files/intake.JPG

ok the opposite threaded hole, opposite of the one you have circled, goes to the heater core, plugs into the firewall. the other heater hose goes to teh top of the water pump. the one you have circled can be plugged up with a butt-plugg, but wrap it in teflon tape jsut for ****s and giggles.