This Week's Update
No big changes to report with my backorder situation, mainly affecting the IRS and Wilwood brakes. I’m in regular contact with FF, and I believe they are trying hard to get my remaining parts. But no firm dates at this time. I’m not the only one in this situation. I want the IRS installed before starting fuel and brake lines, which is really what I want to be doing next. I’ve not done IRS before, and I don’t think anyone has done the 2015 Mustang one yet. So I’m just not comfortable running any lines before I see exactly what I’m dealing with. Then need the Wilwood brakes to finalize all four corners plus e-brake.
Meanwhile, I’ve kept busing making progress in other areas. Decided to tackle the fuel tank assembly and installation. The first two kits I built were not donors but were basic kits. So I bought my own fuel tank in each case. They were pretty generic Spectra tanks. Domestically made, unpainted, etc. This complete kit has the FF supplied tank. It’s not marked, but just based on the box and other components, it appears to be imported. Quality seems decent. It’s painted, which is nice. I like the provided cover better than the standard Ford part. It’s kind of a shiny plastic, and doesn’t have the bump-in for the differential which is out of place for our builds. So gives a nice clean appearance. Important for under the car, right? One caution I would make about the tank. Use a file, sandpaper, emery cloth, whatever, and clean up the openings. They are rough and razor sharp. I can’t think that would be nice on the rubber seals used in a couple openings, or just to protect from cutting yourself. I blew out the tank real well to make sure it was clean inside. Then started to install various components.
A problem frequently mentioned in the past on the forums is having to fill the tank slowly or it backs up, flows over, etc. I think this is mainly related to using a donor fill tube, something that isn’t done too much any more. But one suggested solution is a larger tank vent. I’ve done this on both of my builds to date. They didn’t have donor fill tubes, and I never had fill problems. But I went ahead and got one for this build as well. It’s Breeze #70648. You can see in this pic the difference between the Breeze part on the left and the kit vent on the right. What doesn't show is the much larger check ball and valve on the Breeze piece. It pushes in through the kit supplied gasket in top of the tank.

Next up was the fuel level sending unit. I used the kit supplied part. I did check its operation before installing. First just to make sure it was alive, but also to confirm the measurement range. With a digital multimeter clipped across the leads, measured the ohms at empty (float down) and full (float up). It registered 15.5 – 165 ohms confirming it was doing something. For my last build, the Ford sending unit had the same reading, which turned out to be one of the ranges available in the Speedhut gauge during calibration, so easy to pick the right one if not already using that range.

I need an electric fuel pump for my Coyote build, and decided early on to do an in-tank pump. There are advantages and disadvantages for in-tank and external. But I think it’s generally accepted the in-tank pumps run cooler and are a little quieter. The main downside is they are harder to service or replace. But with the access panel in the trunk, not too bad, so going that way. The Coyote recommended pump is a 255L/Hr unit. I went with one from Breeze. Mark sets it up with a Walbro pump and oversized 1/4 inch inlet and 5/16 inch outlet. Here I have it ready to go into the tank with the filter sock attached.
Here is the top of the tank with the fuel pump and vent installed. I also added -6AN adapters for the inlet and outlet tubes from Breeze. I will use SS flex from here to the rigid fuel lines about 12 inches away on the chassis.

I use a floor jack with a piece of plywood and cushioned with a blanket to lift the tank into position under the chassis. Don’t forget the little plastic bumpers on the bottom of the tank support tubes. Also don’t overlook the manual instructions to straighten the bent seam on the tank by the straps. I admit I missed this at first. The tanks I’ve purchased before weren’t pre-bent like that. The tank won’t sit properly unless the seam is flat. I did have to “adjust” the two front tank supports a bit with a dead blow hammer. The PS about ¼ inch. The DS about ½ inch. They needed to be moved forward just a bit so the bumpers sat flat on the tank seam without running into the tank sides. With the cover in place, the straps snugged up fine and all is good.

Here’s a nice surprise. Looks like the fuel filler isn’t going to interfere with the frame rail. This is a common problem many have reported, and I experienced on my last build requiring me to shim the tank down a bit. I’m not sure what changed. Maybe FF extended the tank mounting tubes a bit. Or moved the frame rail some. Whatever, happy to see nothing special required here.

The tank is now back off, all the openings taped up, and ready to install for the last time later in the build. I cut off the extra tab above the strap connection on the PS. Did the same thing on my last build as well. Although I haven’t experienced it, there are apparently some tank strap setups that need this higher mounting location. But this one doesn’t, so off it comes. I’ll put a little paint on the bare metal, and add a piece on the trunk aluminum to cover the matching opening. It’s an obstruction that is nice to not have in the trunk. Some go even further and lower the other mount out of the trunk like the DS. That requires welding and shortening the strap. It’s far enough down in the trunk that it’s not an issue IMO.

I assembled the Russ Thompson trunk box mentioned in my last update, and used the now installed tank to confirm the location of the trunk box. I centered the sender access panel over the sending unit, and confirmed all else had adequate clearance. Then located the trunk aluminum, marked and drilled for rivets, and started the first of many drilling and cleco sessions. With the required opening for the trunk box now determined, cut out the hole and drilled and cleco’d the trunk box into place. An often asked question on the forums is how many clecos does it take to build one of these? Here I demonstrate it takes a lot. Couldn’t help myself… Really, not that many are required. In these pics you can also see that I’m leaving in the chassis tubing through this area. Many remove these pieces when installing a trunk box, and (hopefully) weld in new pieces below the box and above the tank. I’m OK with the minor obstruction, and happier to not mess with FF’s chassis design. It still gives a ton of additional space.

My last update for this week is a nice surprise. Part of my Coyote build plan is stainless headers from GP Headers. A little over two weeks ago I called Kevin at GP Headers in Minnesota. He said he doesn’t stock them but only makes on order. No problem. Took my name and number and said he would call back in two weeks for shipping info. On Wednesday, he called and said they were ready. Exactly two weeks! Took my address and credit card number and they were on my porch on Friday. I’ve seen pictures, but not seen these in person. I’m not disappointed. Beautiful pieces and amazing workmanship. Of course the proof will be how they fit. But for now I’m a happy camper. In the second picture you can see the center spike in the collector. Similar piece where it goes back to 4 tubes right before the pipe flange.

At this point I’m going to keep plugging away on sheet metal until my IRS parts are here.