Holley Sniper Stealth EFI - Part 11 (Tank Installation)

Today, I installed the new gas tank into the refinished Mustang floor.  Before doing so, I took advantage of the extra space to install the bulkhead fittings, fuel filter, and connected the fuel lines.  I need to fully tighten and secure everything but those initial tasks are far easier done without the tank installed.

 There was some original sealant between the tank and the floor which I emulated using some 3M butyl rubber strips (#08578).  This sealant is probably the best that you could get for this job.  That said, I hesitated a little using it as I know it will be an incredible pain if the gas tank needs to be removed in the future.

I bolted the new tank in place using a set of Scott Drake (C5ZZ-9002-MK) reproduction screws.  I used the replacement rubber filler hose that came with the tank as the original was hard as a rock.  I cut it to fit (3.5") and then installed it with a set of Scott Drake (C5ZZ-8287) clamps.

There are little vertical bumper pieces that can be installed below the rear bumper.  I've not had them in place and don't have interest in them.  I used reproduction bolts I had that matched the originals but used flange nuts on the back of each.  I did this in part to fill those holes but the two going down through the gas tank at the back at the car also serve as the ground for the gas tank and sending unit.  

With everything installed and tightened into place, I connected the sending unit, power to the pump, and a dedicated ground for the pump.  I then secured all the wiring with some 1/4" Tech Flex braided wire covering to help keep is safe.  I now need to find something that will cover the tank and help protect the lines and the wiring as I tend to put things there when going on long road trips.  

The following is what I have left before I could try to start up the car for a test drive:

• Confirm under hood wiring is secure
• Plug all wiring into the Sniper throttle body
• Connect the battery terminals
• Confirm fuel lines are all secure
• Confirm all fuel lines are tight
• Connect the fuel vent
• Connect throttle linkage
• Fill with gasoline

These are the things I'd like to come back to after the test drive is complete:

• Build a bracket for the filter behind the throttle body
• Build brackets to hold the fuel line under the car
• Insulation for the top of the fuel tank
• Rewire and dress up underhood wiring
• Run fans with the Sniper system

Holley Sniper Stealth EFI - Part 10 (Trunk Floor & Tank Test Fit)

This weekend, I worked on cleaning up the trunk floor so that I could install the new fuel tank.  I used a few unconventional options but the final product looks good.

I started with a small, sharp chisel to scrape off the original sealant used to seal the gas tank to the trunk floor.  This was rather effective on flat areas but not along contours.  I switched to some degreaser and a Scotch-Brite pad but that had a very small effect.  I considered a wire wheel but thought better of it.  What I ultimately used was the degreaser with pieces of 220 sand paper which removed the sealant but also prepared the surface for paint.

With all the sealant off, I switched to wiping everything down multiple times with mineral spirits.  As you would imagine, no one has cleaned the trunk floor in the Mustang likely since production.  As a result, it was rather dirty.  I essentially wet sanded with some mineral spirits to as it helped smooth the areas of the rough trunk floor where I planed to overlap the new paint.

I used Rust-Oleum Rusty Metal Primer (#7769830) on the areas where there was some rust and generally where I sanded down to metal.  I then coated the mounting surface and a little out on to the trunk floor using Krylon Fusion Matte Black (#2754).  The final product looked rather nice so I went to eat dinner and let it dry overnight.

I set the fuel tank in place the following morning and marked locations for the bulkhead fittings that will be used to run the fuel lines from the trunk back under the car.  The bulkhead fitting holes are .55" so they are rather large but I was able to put them just off the edge of the tank and they were still on a flat surface.  

Holley Sniper Stealth EFI - Part 9 (Fuel Line Routing)

Beginning at the new Tanks fuel tank, I'll cover how I'm going to route my fuel lines and the parts used for my benefit and that of anyone else attempting the same upgrade.  

I start from the Tanks fuel pump (GPA-4) with a pair of Summit Racing 1/4" NPT to -6AN adapters (SUM-220647B) for both the fuel supply and return lines.  These then connect to a pair of Allstar coated, braided -6AN fuel lines (ALL48465-12) that are a foot long each.  These attach to some Speedflow bulkhead 90 degree fittings (833-06-BLK) and matching retaining nut (924-06-BLK).  This completes the run of fuel lines from the pump to the bulkhead fittings to switch to running the lines under the vehicle.

Under the vehicle, I'm using a Summit Racing 90 degree 40 micron fuel filter with -6AN fittings on the supply side line.  On the return side, I use a Speedflow 90 degree coupler (143-06-BLK) so both lines are headed over to the driver side of the vehicle.  The rest of the run up to the engine compartment is handled by a pair of 14' Allstar -6AN coated, braided fuel lines (ALL48465-168).  I'd considered many different ways to handle it but this seemed the best and frankly the easiest option.

The return line connects directly to the Holley regulator and fuel crossover kit (534-237).  The supply line connects to a Summit Racing 10 micron fuel filter (230123B) that is held in place with a bracket I made and a Speedflow fuel filter bracket (602-500-BLK).  This fuel filter has a 90 degree Speedflow coupler (133-06-BLK) which connects directly to the Holley regulator as with the return line.  This system has everything I need and is about as simple as I could find.  

I started today installing all of these parts at the throttle body.  I ran them straight from the back of the throttle body down the top of the transmission.  At the parking brake bracket, I started running them toward the side of the car attaching them to that bracket safely out of the way.  I then ran them down the inside of the subframe connectors on the inside edge so they would be safe.  While there are probably better ways, I used some 1/4" thick black zip ties to hold them to the subframe connectors.

I'll need to make a few brackets to hold the lines in place.  I'll attach one to the side of the transmission, another to the frame using the original fuel line bolt just in front of the axle, and the another on one of the old muffler bracket bolts that will hold the lines to the frame right beside the fuel tank.  I have some Russell AN line spacers that I can use for these brackets or I might come up with something else.  I've not decided quite yet.

Holley Sniper Stealth EFI - Part 8 (Fuel Tank Preparation)

Occasionally, over the last couple of weeks, I've gone to the garage after work to get the fuel tank ready for installation.  As stated before, I purchased a Tanks kit (TNK-MU-HT-KIT) which includes a TNK-GPA-4 fuel pump, TANK-TAN-ORG sending unit, and a few other items.  

The adjustment process starts with measuring the depth of the tank the fuel sock on the pump is 1/8" off the bottom of the tank.  The return line is about an inch of the bottom of the tank.  

After some cutting of the supplied tubing, a few hose clamps, and use of included zip ties, the correct length fuel pump is ready to be installed.  It comes with a cork gasket that I coated in Permatex 85420.  

The process for the sending unit isn't much different.  I somehow neglected to take a picture of the final adjusted piece.  Essentially, the long metal bracket that has the rheostat at the bottom is cut to fit the tank.  The float arm slides into it and is cut off so that the float a full height is 1/8" below the top of the tank.  This piece came with a rubber and a cork gasket so I just used the rubber one as I expected it would seal better.

Lastly, there is the tank side of the filler neck that has a cork gasket.  I coated it with the Permatex too and bolted it into place.  Everything with the tank is now ready to be installed.  I'll just need to do some work with the truck floor before I install it.

Additionally, I took the old fuel filler neck, used paint stripper to remove all the old crusty paint off of it, and painted it matte black using some Krylon Fusion paint (#2754).  

Holley Sniper Stealth EFI - Part 7 (Temporary Wiring)

My most recent work with the Mustang has been to complete my temporary wiring of the Holley Sniper system.  This included running a pink wire to the back of the ignition to get consistent ignition power, connected to the negative side of the coil, and then connected the tach input to the Sniper system.  I made not attempt to clean up the wiring but more to set it up in a way that I can temporarily zip tie it so that I'm able to drive the vehicle without risk to any wiring.

Ultimately, the plan is to stop using the Flex-A-Lite 31147 fan controller and operate them using the Sniper system.  This will give me an exact point of activating the fan and to control them separately if I choose.  This is far more accurate than the current solution of watching the gauge until I reach 180 and then turning the knob on the Flex-A-Lite controller until the fans turn on.

Additionally, before going on Power Tour in 2023, I installed a relay setup to provide full 12v power to the headlights when they are on and limiting dependence on routing power through the light switch itself.  However, that relay setup failed almost immediately.  I'd like to remove or at least reconsider how that works.  

With this work and my desire to just keep it clean looking with the additional Sniper wiring, I'll need to reconsider routing and wiring management a bit so that it is done to my satisfaction.  I really want to at least drive it some to confirm it works before pulling it further apart for that work.

The end product really isn't something to take a picture of and share with others.  However, I'm including it to document this point of the install process.  While the main things are wired, not everything is zip tied up in this picture and the wiring isn't plugged into the Sniper throttle body.

With the wiring completed to a testing state, I'm going to turn my attention to the fuel system.