The lock ring can be had from your favorite "stealership" for about $5 part number 25124032.
I would recommend at least three people to lift the bed off. The bed weighs 198 pounds by itself with the tail gate adding another 32 pounds for 230 pounds total. There are two ground wires. One is by the fuel filler neck attached to the underside of the bed. And the other is attached by the rollpan to the frame. On this ground, there should be a plastic clip that holds it to the frame. Remove the plastic clip that holds the ground wire to the frame or else the bed will get snagged by the ground wire. When you reattach these grounds, I would recommend wire brushing where they attach and giving the area a liberal coating of grease. Loose grounds can/will give you intermittent problems that can be a royal pain to trace.
Before you remove the lock ring, blow off the top of the tank with compressed air to keep all the dirt from falling into your tank. Water Displacement 40th attempt (how WD-40 got it's name) will work good but, PB Blaster will work best. I have used it on two syclones and one typhoon fuel pump swap with great success. Make sure you Give it a few minutes to penetrate. When you put everything back together, coat the top of the fuel sending unit/lock ring with a good coat of grease. This will help keep corrosion in check for the next time you have to get in there...
As far as the fuel pump goes, be sure to "loose" the pulsator. It's a metal/plastic deal that hangs on the side of the fuel pump. It looks like a mini brake master cylinder. It's *supposed* to dampen the vibrations of the pump and quiet it's operation. But it can cause pressure problems so, just get rid of it. Your new fuel pump should include a short length of rubber hose and two hose clamps for this purpose. You will notice a very pronounced whine to your pump after you get it installed. Don't be alarmed it's the sound of a high pressure fuel pump pumping happily away. The absence of that sound will let you know that you need to do this "dance" again.
BTW, don't forget about the three screws that hold the fuel filler tube to the side of the bed behind the fuel door. The bolts that hold the bed on can be a chore to remove. A light coating of grease will help with installation and future removal. Make sure that you have something to set the bed on after you take it off. 55 gallon drums, saw horses, etc. If you set the bed down on the cladding, it WILL break it!
Lastly, with the bed off it's the perfect opportunity to clean some areas that never see the light of day. I pressure washed my frame as well as the back of the cab and front of the box. The cab and box then got a HUGE coat of wax. FWIW, Ron Gregory in Garland TX is the syty Walbro fuel pump/Jabsco IC pump guru. Check him out here:
http://www.autoperformanceengineering.com/ HTH's
Mike Campbell