Oil pan change?
Changed my 340's pan -with a stock one- in the car it sucked. Mostly due to the headers being in the way. Hardest part is keeping the gasket lined up.
When I had a pan leak on my new engine with a milodon pan I just pulled the engine way way easier. Plus there was about a 1/2 notch on the righthand front lip of the k-frame to make it fit. Driver side clears by lots