So is it finally fixed? They may have fixed the large leak the first time, and tried to help you out on the small leak by tightening the oil pan bolts, which likely made it worse. A rough guesstimate would be about 3 hours to change the oil pan gasket with the transmission installed. Generally, the pan comes off by unbolting the fan shroud, removing the motor mount through-bolts and jacking the engine up from below with the car on a lift. There are a lot of variables here too.
I doubt the postons was warped. It's very very thick aluminum. But the can be hard to seal. With the way they do the original to block for the pickup tube I don't see how you can use a normal pan gasket at all. I've had my pan for almost 15 years and have never used a gasket. There were some when knew that didn't fit right to the timing cover so careful examination needed to be done and the front part of the pan modified to get angles and clearance right sometimes. Other than that rtv all the way around. Now the rear is a trick, normally mine is done on a stand with the engine upside down. But use 3 very large beads on top of each other. And set the pan done very evenly. On the front and rear I used some the squeeze out to make a secondary external layer between the pan/block/cover up front and pan/block/rear cap on the back. My pan has the girdle in so so I have a few more steps. I also rtv the lower half on as well. I would not trade my Poston pan for a at unit at all. For 2000 I will pull your motor, replace every gasket and seal and put it back in. 2000 for the work in question is beyond crazy On a side note, I'm pretty sure there is no way I could get my Poston pan out with the motor in the car. But mine has the girdle built it. It barely clears the crossmember on my 72 car. And my motor is moved rearward which should make it easier. And kniwing how the rear seal is i woyld never try to do it in the car. I can have the motor and trans out on the floor in about 45 mins. Why fight it from the bottom if you dont have too. I know a stk pan you can, done it the roll new bearings in at the racetrack b4. You can get all 8 rods and all 5 mains in from the bottom.......not easy but can
I have a Poston pan and it is PITA. If you do not know what you are doing with one it is probably best to go with a different pan.
Like Bens99 I would pull the motor to put that pan on. Everything must be perfect for them not to leak. Especially if you have the girdled pan.
Mine also has the griddle, two piece so it’s much easier then a one piece.. Supposedly all is fix. Heading tomorrow to pickup and will report back. Let’s see what I negotiate on the hours. Thanks all for the info and help.