pK1spooled

Hi, got a little problem. Trying to do Ls vtec with my GSR head, and the plug near the distibutor for the oil line is stuck. Its an 8mm hex, and i have hex keys as well as sockets, and I put alot of leverage on it and it began to chew up the plug. I can still fit a hex key in it so its not that bad, but what the hell do I do to get this thing out? The head was recently cleaned and refinshed by a shop, does this have anything to do with it? Can i apply heat to it with a torch? i know its aluminum and I dont wanna screw it up... I can try an impact gun on low setting, by again im afraid to without asking first...

any help out there please!