to answer your question, no you can not replace the oil pan without pulling the engine, you might as well get you a cherry picker or a set of tripods and unbolting the engine, it isn't really that hard, a few wires, two motor mount bolts, and some bell housing bolts and it's ready to come out, you can do it all in about a day if you know what your are doing
labor time to replace engine in a 1984 chevy c60
You can replace all of them BUT the 2 in the rear of the engine block with out pulling the engine. To remove the rear ones you can either pull the transmission are remove the engine your choice.
closest to the pulley/belt.
Ford Pinto Gremlin Chevy Chevette Fita Uno
yep, though you may have to replace the mounts.
check this site out
Replace the fan clutch that is on the front of the engine.
No you can not. It is a solid round seal that slides over the back of the crankshaft where the fly-wheel bolts up to the crankshaft.
To replace timing chain on a 3.1 Chevy Lumina engine, you need to first make sure that your motor or engine is turned off. Then you need to remove the chain and replace it.
Take it to a mechanic.