This is your basic starting point. Note that I did NOT have to remove the rear floor support, only the pressboard piece and the spare tire. The fuel pump is already unplugged.

This is with the fuel pump cover removed completely - note I pulled the wire out of the cover. It makes it a LOT easier to work with. BTW, the butyl gunk holding the cover down can hold it down TOO well, and you may bend the cover getting it off. I didn't have that problem, but others have. It also depends on how warm it is when you are removing it - it comes off easy in summer, MUCH harder in winter.
The important parts?

• The blue piece is the check valve, you will need to bend the bracket towards the electrical connections in order to pull the valve off. Then remove one hose end and push the valve out of the way.
• The fuel fitting you will grow to hate is on the right of the hole.
• You will see 3 little rubber "knobs" - these are part of the gasket, and help hold it on the pump cap.

This is your closeup of the &(*#$ fuel line fitting. You will grow to hate this thing. Note how mine is a little chewed up. I tried every which way of getting that fitting loose, even using the right 14mm wrench, and it would not come loose. I finally had to grab it with some large vicegrips, and strain a few muscles to crack it loose. Then I took a Dremel to the fitting, and smoothed it out - now it works with the 14mm flare wrench again.

Don't believe me and the many others on the Digest that say that fitting is hard to crack loose? Here are 2 more pump fittings, one that came off relatively easily, and one that had to be nearly destroyed to get it off. Note that the "easy" one was still slightly mangled.

If you still want to attempt to get this fitting loose, putting a wedge under the flare wrench will help a lot (courtesy Tim Fisher). Otherwise, read on...

(Addendum to the above - others have found it easier to disconnect the fuel line farther forward near the front of the tank. There is a fitting there that seems to be easier to crack loose for most people. However, it requires getting under the car. My way, the fitting is much harder to crack open, but can be removed easily in the future from above the car. It's up to you. If you DO undo the front fitting, you can then undo the rear fitting once the pump is out, so in the future you can use the rear fitting.

NOTE that 2nd gen cars should DEFINITELY use the forward fitting, as the rear "fitting" may not actually be a fitting.)

This is your &(*#$ fuel line fitting again. Once I got it loose, I took off all six pump retaining nuts (one was hidden under the check valve and its' rubber hose), and started to lift out the pump. Hm, some resistance, it's not coming out. Lets do the intelligent thing, and check it out. Hm, feels like a gasket. HEY!, so that's what those rubber knobs were for! The gasket tends to stick to the tank, and the knobs hold it on the cap. Gently dislodge the gasket from the tank, and wiggle the pump assembly in many different directions to remove it. You'll figure out which directions when you get to this point.

IT'S OUTTA THERE! If you are enterprising, you will stuff paper towels in the tank opening, and clean the gasket surface. I was tired and pissed, I didn't. DO make sure to stuff some paper towels in there to keep stuff out until you put the pump back. Use a flashlight to check the inside of the tank for junk - mine was clean, others' have not been.

Here is the pump, ready to work on.
Note a few things:

• The rubber gasket is in one piece, because I was careful.
• That bottom Philips screw will most likely not come loose using a screwdriver. Grab it with pliers or vicegrips to crack it loose first.
• Obviously, don't bend the float pickup rod ;-)

Pump removal:

• Remove that bottom Philips screw, and slide off the bottom bracket.

Pump removal:

• Remove the rubber insulator and fuel filter.
• The clip that holds the filter on is a pain to remove, but rock it off bit by bit, DON'T just yank it, it will break, and you will be SOL. Go ahead and pull the filter off so you can store the old pump without fear of breaking the filter.

Pump removal:

• Slide the positive terminal boot up, and remove both terminal nuts.
• Pull the pump straight down, and watch for little parts.
• SAVE all of those little parts with the old pump.
• NOTE: Do NOT forget to pull the O-ring out of the fuel line hood if it does not come out, and save it with the old pump!

Here is the stock assembly with the ND uprade pump and the Walbro pump. While the Walbro pump is smaller, it vastly outflows the ND pump and stock pump. Note the stock pump has the lower spacer, O-ring, and upper cap still on the pump outlet.

Here is the stock assembly with the lower spacer, O-ring, and upper cap removed from the pump outlet.

Here is the stock assembly with the old O-ring and upper cap, and the Walbro pump with the old spacer, new O-ring, and new upper cap on the outlet.

Installing the new filter and ring clip on the new Walbro pump.

The new Walbro pump in the assembly, with the new bottom rubber spacer and rubber foam sound insulation tube installed. Note that the ring terminals are still on the old wiring. This will have to be changed.

The new Walbro pump in the assembly, with Walbro wiring plug plugged in, wires close to where they need to be. Note that the ground ring terminal can be used on the Walbro plug, but you may need to cut the positive wire ring terminal off and use a crimp terminal or solder and heat shrink tubing (preferred) to complete the install. This is the ONLY part of the install that requires modifying the stock setup, and if you save the old stock wire you cut off, it is easily reversed. (NOTE: Slide back the rubber boot on the top of the stock positive wire to see if it is bolted down - some 1Gs have it riveted down like mine and require splicing of the wire, but some 1Gs have the wire bolted down, so all you have to do is unbolt the stock wire and bolt the new positive wire down)

Here is the pump on the assembly, with the plug that came with it being wired on. Notes:

• I am using heatshrink tubing on the positive feed wire. DON'T use electrical tape, the gasoline will dissolve the adhesive right off.
• The stock positive wire IS being cut off. If you reverse this install, you will need to solder that piece in the foreground back on (if your stock wire wasn't bolted down).
• (IGNORE the hose clamps, this pic is taken from the "Mustang: Walbro VFAQ)
• Be careful when putting the pump up into the fuel feed line - the rubber O-ring should be lubed with some grease, oil, or spit (hey, it works) so that the O-ring slips easily into the feed line. If it does not, the O-ring can kink or tear, and the car will be hard to start after sitting a few minutes, as the kinked/torn O-ring will allow the fuel to bleed out of the feed lines. The symptom will be that the car will take several seconds to start after sitting more than a minute or 2, but starts right up if you turn it off and then immediately start it back up.

So, how well does it flow? Here's a graph of the GSS307 pump, which this 1G kit pump is is similar to. Note the major difference in flow between 12 and 13.5 volts - my next plan is to wire in 10 or 8 gauge wire back to the pump wiring, and put a relay in there, so the pump gets as much voltage as possible. When I do that, I'll add the pics in here.

Another graph comparing the flow of the stock pump to the Walbro DSM pumps is here.

A note from Gino Valic in the Talon Digest:
"I recently discovered when installing my Nippondenso pump in a 91 gsx that the O-ring needed for the pump is the same one used in the Walbro installation kit. I wound up using the O-ring, retaining cap, and strainer clip for my pump installation. I have found the part # for this O-ring which anyone should be able to find in Autozone or PepBoys autoparts store. The O-ring is made by Borg Warner and the part # is 274571 Fuel injection seal. The list price is $4.25 and it cost me $1.98. The kit include two O-rings so if you screw one up, you have an extra."