Build Thread 429MII's Build Thread

Got a 65 mustang gas tank. This will take up less space in the undercarriage and make space for dual exhaust split evenly underneath.
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and make space for dual exhaust split evenly underneath.

This is interesting, Ive been thinking dual too. So far it seems a double hump crossmember and this muffler was the way.
All on one side. That or side exit.
There not going to be a lot of gas tank welding right?
I've been having a hard time with 'chevy orange parts' and all.

IMG_20160413_125322.jpg 2007_0201exhaustnewIIMustang0002.JPG IMG_3825_1024x1024.JPG
 
Unfortunately the Fox tanks are so damned wide!! That's what I installed in my car, there's a video on youtube that I made a few years back for anyone interested, the link is shared here as well. I ended up just running dumps at the axle, if I wanted to run the pipes out the back of the car I'd probably have to have them wrap pretty close to the tank and exit through the spring shackles, or somewhere very close to it! Running the Fox tank allowed me to keep the spare tire well and not have to make any modifications to the body to speak of. :) If you decide to watch the video I'm gonna apologize now!! My narrative skills kinda suck!! lol

Here's the link just to save you some time.....

View: https://youtu.be/pEHGqIu7FJQ
 
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Not meaning to be a wet-blanket, but please do some research on the (relative) safety of the drop-in fuel tank. Depending on your intended use, it may eliminate your car from competition, and potentially cause an issue with your insurance.

Aside from the challenges plumbing in the filler neck might give you, a fuel cell dropped into the spare tire well would be significantly safer. Even then some regulations would want you to wall it off from the passenger cabin.

If you're completely aware, then carry on by all means. :) It's a very limited, though calculated, risk - personally I prefer something more than air between my cigarette and a rubber filler neck hose (another calculated risk).

Even then, you might consider 'tank armor' considering how our cars or prone to not allowing the doors to open after minor collisions. If you want that piece of mind.
 
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First of all, thanks for your concern. I appreciate any and all opinions on any aspect of my build. I am not a know-it-all and although I have a fair bit of experience under my belt there are always ideas and concerns to weigh when modifying a car, especially one with a few more horses than was original. If we keep each other safe out there the hobby has a better reputation, and..well..we are safe.

The safety aspect, although not worrying me personally, could cause issues should a tech inspector at a track have issue with it depending how fast the car went. I do not really intend to track this car, so that is not too big a deal, and as the tank will be pretty much stock appearing, I think they would not even notice it. that being said...

The tops of these tanks are pretty tough, and do not tend to leak up through the part that forms the trunk floor. They are designed to be a trunk floor. Yes this is a hatch car, so open to the interior, I see where you are going with that, but in essence there is no difference in a 60's era trunk vs a Mustang II hatch in that neither are sealed from the occupant area anyway, with only seat fabric and fabric package tray separating the two..fuel being a liquid and a gas, will travel the same regardless of a seat in the way. Although I do not smoke, I would not build it in such a way that any fumes or rubber or liquid would leak or be accessible anyway.

I think actually a standard type fuel cell is more hazardous than this mustang tank in a hatchback installation. All the fuel cell filling and sending parts are on top, and vented to the interior unless an outside fill tube is adapted, which still leaves the sender to leak inside the car. Most popular fuel cells are plastic which also seems less safe. Granted if I went for a circle track steel and bladdered outside filled fuel cell for 700 to 1000 bucks it would probably be safe, but I am going for a different look.

I do have a possible alternate idea of mounting the 65 tank below the floor, which would require cutting out the spare tire well also and re skinning the floor. I may yet do that. The drop in mounting would work alright, but I find myself wanting to be picky on how it's mounted which would involve fabbing up a shelf lip ala' 65 mustang trunk for it to mount to neatly and correctly. As this would be a lot more work, I think I can successfully under mount it once the floor is re skinned with perhaps less fabbing. I wasn't planning on using the stock filler location anyway so filler plumbing will be a fab job anyhow. The fuel filler will exit the rear under the licence plate. I am running the stock rear battering ram bumper, so protection is as good as any car. The 65 tank is quite shallow, so It will not hang down even as much as the stock tank.
If none of it looks safe when I mock it up, I will not go with it. It's kind of hard to say at this point until it is mocked up.
 
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If the early mustang tank where converted for a fuel inlet on the side, the solution with the removed spare tire well (and reskinning) would be the perfect solution IMO. But I'm not familiar if this is easy to to?!
 
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It could be converted for fuel inlet on the side as well. Only difference would be the little bit of welding or soldering involved. However, most fuel tanks are galvanized and not super safe to weld on as noxious gasses are released when welding. I think cianide if I remember correctly.
 
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If you watch the video you can see that I welded on the Fox tank. I was in a well ventilated area and rinsed the tank out the best I could a couple of times with water. I had absolutely no issues with anything catching fire or anything else. Now I wouldn't advise welding on a fresh tank or anything, but mine had been empty for quite some time beforehand. What I can say from experience is that they don't like being welded on too much. Even with the prep I did it ended up being a little porous, so I ended up having to use Red-Kote to seal it.
 
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Is it suffiecient to cut a hole with a hole saw and use the filler neck pipe seal on the deburred hole?!
I have the following parts ordered to build my own filler neck pipe (based on 2.25 stainless steel pipe):
https://www.summitracing.com/int/parts/sdk-c8za-9047/overview/
https://www.summitracing.com/int/parts/sdk-d1zz-9072/overview/
https://www.summitracing.com/int/parts/sdk-c9zz-9034-a/overview/

My original filler neck pipe is in a bad condition and i like the idea to have the hose to connecct the pipes...
The diffrence to the Mustang II specific filler neck pipe seal is the diameter, the price and the availability ;)
 
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Is it suffiecient to cut a hole with a hole saw and use the filler neck pipe seal on the deburred hole?!

The best answer I can give is maybe?? It might take a little more than just cutting a hole and installing that seal though. The stock tanks have a rolled lip on them which make them thicker where the seal contacts. I will make an educated guess and say that they did that so as to not cut through the seal due to vibration. It might work for a while, depending on how tight your seal is, but I don't think I'd trust it long term.

Now if you were to build up some thickness around your saw cut, that might work a bit better. But again, I think you may want to radius the edges of the hole so there are absolutely no sharp edges.
 
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It might work for a while, depending on how tight your seal is, but I don't think I'd trust it long term.

Your absolutly right. I checked my tank and the seal...
That bead on the tank that holds the seal is quite thick. I think that removing this section from the old tank and welding into the "new" tank whould be the way to go.
Here is a picture:
IMG_20190504_103208.jpg
 
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That is exactly what I did with the Fox tank. The Fox car's filler tube is a little smaller than the II's tube which necessitated the change for me. As you can see in the video, I kept the auxiliary fuel tank in the quarter panel, so I needed the proper sized hole for everything to work. The wonderful part about welding the fuel tank and where the filler tube is located is that it doesn't need to look pretty, just functional. As I stated before, I ended up having a little porosity in my welds and I ended up coating the inside of the tank with Red Kote. If you're looking to cut that section from your old tank to weld it onto another, I would advise you to be prepared for that scenario.
 
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Ok a lot happening this weekend. I should get the front a-arm and spring chop completed, new urethane bushings, new balljoints act wrapped up. Also hope to start chopping out the rear hatch floor for fuel tank install. I will get some pics up this weekend.
stay tuned....
 
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