Ed,
I have replaced the oil pan in a Quietline (mine was a 1450, but the steps are basically the same).
The way I go about pulling the engine in a Quietline (you have to pull the engine to replace the pan, since the pan is what is holding the engine to the tractor)
1. Unhook supply wire from tractor from headlights (if equipped)
2. Remove side panels
3. Remove hood and front grill casting (can be done as 1 piece)
4. Shut off valve on fuel tank, unhook fuel line from carb, and remove firewall/tank as a unit. On the newer Quietlines, the wiring harness that goes to the lights, starter, voltage regulator and PTO go through a hole in the firewall, this will all need to be disconnected before you remove the firewall. If it lies in the frame, it still needs to be disconnected, but can be done after the firewall is removed. Also, remove the throttle and choke cables.
5. Unbolt the 2 bolts from the ragjoint on the driveshaft to the engine (the other 2 hold the ragjoint to the driveshaft and don't need removed)
6. Unbolt the 4 bolts holding the pan to the ISO bars, 2 inside the front axle channel and you have to lift the tractor and secure it up, and tilt the axle down to reach these bolts, they are 9/16 head...
7. Hook a lifting device to the lifting eye near the sparkplug, start to take the a bit of the weight off the tractor and slide the engine forward so it will come free of the driveshaft. The driveshaft has a little "nub" that slides inside the hub on the back of the engine.
At this point the engine should be loose, carefully remove it and replace the pan. I normally try and find an older pan since they are cast iron (all the ones I've seen/had that were cast iron were painted yellow) as the Quietline has an aluminum pan.
Also this would be a good time to inspect/replace the ISO mount rubbers on the rails, and I highly suggest, since you are this far, to do the "cradle mod"
From Charlie's FAQ's: 23. How do I fix my Quietline Engine ISO Mounts and Bracket?
http://cubfaq.com/isomount.html
I just did this on my 1650, and did it 8 years ago on my 1450 and the ISO mounts are still in good shape.....
Reverse the above to reinstall. Not a really hard job, just give yourself most of an afternoon to do it.
Dad and I have pulled and replaced enough engines in Cubs over the years we can do it in just a few hours, but if you have never done it, take your time and all should go well.
Don't forget to get a new pan gasket before you tear it apart.........