Submitted by: Grifter
Visit the Lincoln Mark VIII Forum for more help
Replacing the stock Lincoln Mark VIII fuel pump will help with fuel delivery. The Walbro fuel pump gives you 255 LPH which is a significant improvement over stock. Additionally, Ford discontinued the stock pump some time ago so you might as well step it up a notch if you need to replace your pump. The Walbro pump is widely considered to be the best pump for the money for the Lincoln Mark VIII.
IMPORTANT: You NEED a 1996-1998 Cobra Mustang fuel pump. The non-Cobra units do not have the same style of pickup tube, and will not work. The Cobra specific units do not cost anymore than the non-Cobra units.
This article is for the 2nd gen (1997-1998) Lincoln Mark VIII. If you have an earlier Lincoln Mark VIII, we have another article Gen 1 Lincoln Mark VIII Walbro Fuel Pump Installation
Disassembling the Lincoln Mark VIII Stock Fuel Pump
Here is what the stock fuel pump assembly looks like when you remove it from the fuel tank.
Remove the 5 5mm screws from the lid. 3 hold the lid to the basket, 2 hold the fuel feed and fuel return lines to the lid. That leaves it looking like this.
Undo the stock wiring connector, leaving the pump in the basket. This is what you will have then.
Pull the pump out, at this point it is not attached to anything, so it just comes out. Remove the fuel sock from the bottom of the pump. It just pulls off.
Reassembling the Lincoln Mark VIII Fuel Pump with the Walbro
On the top of the stock pump, there is a rubber isolator about 3/4″ tall on the pump itself. Remove that and put it on the Walbro pump. It is a TIGHT fit, you will have to massage it on there but it will fit, its a stretch. I put the stock fuel sock onto the new Walbro pump as mine was not overly dirty seeing as how my stock pump had been replaced along the line. That will leave you new pump that looks like this.
Drop the new pump assembly into the basket.
Test fit the lid back on the basket with the Walbro in the basket. You will find that the lid does not seat all the way down like it did with the stock pump. Like shown here.
The fix for this is easy. Go ahead and remove the lid again, leave the pump in the basket. Flip the lid over and look at the area where the fuel pump protrudes through the lid. There is a circle of plastic that keeps the pump in place so that it does not move around in the basket. This needs to be shortened to accomodate the slightly longer Walbro pump.
Take a grinding tool of some sort, such as a Dremel or mini air die grinder, whatever you have available, and whittle away at the circle until you remove enough material so that you can get the lid to sit flush on the basket and still hold the pump in place. You will find that the rubber isolator you took off the stock pump and placed on the Walbro pump fits nicely inside the circle, making a nice seal. Try to get the depth of the plastic as close as you can to make a good seal, but its not overly critical. The isolator takes up difference as much as it can. Here is a pic of how I modded my lid. Note I left the plastic mess on it to show the removal of plastic. Clean yours well and remove all plastic dust and debris before reinstalling everything.
Now you are ready to put it all back together. Take the 5 screws and reattach the lid to the basket with the new pump inside. Now its time to take a look at the electrical side of things. Compare your stock Lincoln Mark VIII fuel pump wiring to the pigtail connector supplied in your kit.
Try putting the stock connector in the pump, and you will see that the shoulder of the connector does not allow the connector to sit deep enough in the fuel pump to engage the locking tab on the stock connector. Looking back at the pigtail supplied in the kit, notice that the shoulder of that connector is about 3/16″ (give or take) higher than your stock one. Take and trim off enough of the shoulder on the stock connector to allow the plug to sit deep enough in the pump to engage the locking tab. I used a sharp carpenters knife to trim my connector, a dremel would do the trick, just be careful not to trim too far into the plug and hit the wiring.
Plug the modified stock wiring back in the pump, and your done!
Here is your finished unit.
As with all mods, do this at your own risk. I (or Lincolnvscadillac.com) cannot be held responsible for information within. The process might vary slightly from car to car. This is just an overview.: