I am new to this forum, but have read the posts related to the vortec head conversion. after experiencing wild temperature spike a couple years ago (and not knowing), I read about the external bypass from the intake to the water pump port and it fixed the problem. the question that i have yet to answer, is how exactly are the vortec heads cooled? my thermostat opens at 185-190 F and the intake never exceeds 195 F, but my valve covers get extremely hot and wonder if the heads are being propely cooled. I'm talking so hot, you can't even touch them. just doesn't seem right to me. any help would be much appreciated!