After taking the bolts out of the motor mounts, you can jack up the motor with a block of wood under the harmonic damper. Put a couple of 2x4's between the motor mounts and the frame brackets for support and to keep it up high.
The 250's came with neoprene seals.
If your pan is tweaked to the point where the bolts don't line up, you'll probably need to sight along the rails and see if there is any way that a judicious application of a BFH will straighten it up. Also, I've had to use short studs a couple of times in the end holes (5/16") and 1/4" ones near the center of the pan rail in order to get it all to line up. Actually, most of the factory GM engines after about '88 have studs in those end holes. You can certainly leave the studs in there instead of taking them out and putting in the original bolts.
You can use a light application of 3M weatherstrip adhesive (aka "gorilla snot"), or some silicone to hold the new gasket up on the block. Personally I prefer to paint the block and stick the gasket right onto it. Use a rag and brake cleaner to wipe down the metal before painting. When the paint has dried enough, it's a great glue and sealer and will not allow the gasket to shift while you're putting in the bolts. Those studs I talked about will help you to line up the gasket when you stick it to the paint.
The only other thing I'll suggest is to jack up the motor and drain the oil overnight before you pull the pan the next morning. That way you'll get a LOT less oil drips on your face while working under the motor.
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David
newbie #4153
