[dsraven]

if you end up doing the intake gaskets, pull that thermostat out and redo the gasket there as well. if you don't already have one, install a gm branded (ac/delco) thermostat. one with the little check valve looking thing in it. that allows air to be purged better and also any steam can get past the stat through the little hole. install the hole side in the highest point (so at the front normally) so air can purge through. personally i have changed lots of stats over the years and will use nothing but OEM parts there. thats how much trust I have in the aftermarket stats working correctly for any length of time. also, check that the stat fits the recessed area of the manifold/stat housing so the gasket has a chance of sealing correctly and the housing doesn't crack when torquing down the bolts.