I haven't tried it on a full size car like yours, but it is often possible to change the oil pan without pulling the engine on a FE, but it is still an involved process. I did this on my Cyclone years ago, you need to remove the sway bar and anything that will interfere with pulling the oil pan forward past the crossmember underneath the engine. Remove the oil pan bolts and break the pan gasket seal, lower pan as much as you can at the front of the engine ( maybe a inch or so ) and remove the oil pump bolts, drop the oil pump into the oil pan, slide the whole works out forward. Re-assemble in reverse order. It can be tricky bolting the oil pump back up and getting the oil pump drive in place, and not to smear the gasket sealer while assembling, but it can be done.
As far as oil pans, you didn't say what you have, if it is the old Ford Muscle Parts pan they are a good pan with baffle, I would try to have it fixed if possible. For a new pan I like the Milodon #31130, it looks most like a original Ford pan. I think all the name brand extra capacity FE pans are fine, Moroso, Canton, etc. The "T" shaped pans sometimes interfere with headers, but since you didn't have those it's probably not a concern.