I just had this experience, so I can relate. I wanted to do an extraordinary job on getting mine sealed properly. Reason being, old old pans have their problems. Mine had a few stress cracks, and a hole from a rock. But after all the repairs I made, my pan leaked like a sieve! Here are a few things to look out for:
1) After removing the pan, look carefully at the pan around the 22 holes. They need to be very flat and not all pushed in due to overtightening. With a dolly under the pans lip, use a nice flat body hammer to pound those holes back to where they belong.
2) Scrape ALL of the old gasket sealer and crud off the surface of the pan mating surfaces. Lots to do here. Make yourself comfortable under there with plenty of light.
3) Get some Lacquer Thinner and wipe down all of the mating surfaces. You have to get all of the oil residue off the mating surfaces so the new sealer will stick. Once you get the engine all clean, hit the pan too.
4) If your bolts are a screw with a star washer, do yourself a favor and add a flat washer. You need something to distribute the force so all that pounding you did doesn't just bend up again. Put the flat washer first, then the star, then the bolt.
5) Put the gaskets on the engine first. Gasket sealer, just spread with finger, then put cork side pieces on first, rubber end pieces on second with only sealer on the engine side. Add a dab of sealer at the rubber to cork junction. Do this on engine side only. Once the gaskets are on the engine side securely, wipe down the gasket surfaces with lacquer thinner to make sure you dont have any sealer slobbering out onto the pan side.
6) Bolt down the oil pan with no sealer on the pan side. Tighten only by hand. Wait till the next day, then remove the pan. This is a critical step to remove the air pockets and such that can cause leaks on new installations. Once your pan is removed, you can be assured that the gasket is installed and will not move on you. Its well worth the extra time.
7) Wipe the pan down again with Lacquer Thinner and then apply a finger swipe coat all over the cork sides. On the ends, apply a more liberal bead on the pan OR on the engine, your choice and then hand tighten the 4 larger bolts on the corners, then finish with the final 18 bolts by hand starting in the center of the engine on both sides.
I have been running the heck out of my engine and no leaks whatsoever. That is the outcome you are looking for. Good luck!
Oh, when the pan is off, also make sure the threads on the oil pan plug is in serviceable condition.
