BlackSheepHB

I’m pulling the left cylinder head on my ’94 Z28 due to a blown spark plug that striped the threads. I’ve got the head almost ready to come off but I’ve run into a snag. The engine coolant crossover pipe that is connected to the back of both heads it the problem. Dam near impossible to get access to it and none of my sockets seem to fit. Can’t really see what I’m doing back there but my 5/8 is too big, 9/16 to small and 15mm fits but with lots of slop. Is there a special tool required for this?