I'm halfway through replacing the timing belt on a '97 KE, and I've run into a snag with the front bank camshaft sprocket. The oil seal is leaking badly, and needs replacing. I've got a new seal, but the problem I'm having is that the sprocket is on so tight that I've already bent a screwdriver trying to loosen the bolt.

I've already given it a blast with some penetrating spray, but is there anything else that might be worth trying?