[WFBowen]

Dave:
Not too big a deal. Drop the motor, pull the flywheel, pull the old one and tap in a new one. Just make sure when you pry out the old one you work very slowly and avoid putting any nicks in the case. There is an installation tool for this, but if you work very slowly putting the new one in (keeping it flat) by gently tapping it with some wood, you'll be okay.
When you say it's leaking a lot, if I put a clean pan under the car and you left it running (hot motor) , approx. how much oil would I see in 10 minutes? A teaspoon? More?
Also, how long did you run the motor? Did the motor ever leak before you stored the car?
Bill.