Anyway you look at it, it wont be a really easy job. But its not THAT difficult.
You could leave the motor in the car, but this would end up probably taking longer IMO than taking it out to do the job. Not to mention it would be more difficult to get the new pan gasket to seal properly.
If you want to leave it in there, you will have to unbolt the motor mounts and raise the motor as much as possible with a hoist. I'm not sure, but you may even have to unbolt the k-member and move it down some to be able to fish the pan out.
I would reccomend just taking the whole motor out to do it. If you've never done it before, its not that bad of a job. Most of the wiring will only go one place, so its hard to get mixed up on that part.
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, production numbers, VIN decoders, modifications, troubleshooting, power adders, DIY tutorials, and more!