Doing that "in the chassis" would never happen in MY driveway.
That engine would come OUT, so I didn't have to work on my back like a prostitute for the whole job. Flip the engine over on an engine stand, rather than flipping the worker over on the concrete.
Likely get a better job done with the main seal, pan gaskets, etc. High mileage? Timing set, rings, head gaskets and valve job. MAYBE bore + pistons, crank grind, block decking...