[427sharpe]

That is the permaseal from the head gasket, and it should be there. It is mfg onto the gasket to help seal small imperfections in the sealing faces. Clean it before installing a new gasket. Before re-assembly, take a GOOD metal straightedge and lay in across the block both across each cylinder and transversely acroos the entire head surface and check for gaps between the block and straightedge. No more than .003-.004 should be there. Do the same on the head, which is easier to see because you can do it on a bench. If you find a gap, a machine shop is in your future! If it all looks ok, take the head and have it magnafluxed and pressure tested...should cost about 75 bucks total...if is passes these, it should be fine to reassemble. If you run the car hot, you might consider head studs instead of bolts, try ARP. Also, some gasket mfgs require you to RETORQUE the head bolts after break in....ck with your supplier, or better yet, use FelPro Permaseals and forget it.