Great Timing Cover "Pains"

I've seen worse looking covers that didn't leak. Early covers in good shape are getting fairly hard to find. But, to answer your first question, if you don't have access to an impact gun, try using a breaker bar and a big hammer. If that doesn't work, they make flywheel locks that attach to the ring gear and hold the crank from turning. Not sure which trans you have and if one of those locks is available where you are. I'd probably just break down and get an impact gun. They have all sorts of uses. I assume you have a puller for the balancer once the bolt is removed, right? Use a three jawed one, not a 2 jaw, and one that bolts to the center hub, not the other ring.