Oil pump swap

Hey Guys,

I'm having oiling issues with the 318 in my 1970 Dart, so I'm thinking about replacing the oil pump.

Can anyone tell me what's involved in this kind of swap, and what kind of headache I'm looking at? Can it be done with the engine still in the car? And what's a good oil pump to use? Is the stock replacement OK or should I go with an aftermarket piece?

Any help would be appreciated. Thanks...