B body tank in A body

Hellooooo FABO!
I have searched to no avail. I know somewhere on the forum I have seen a member cut out the spare tire space to put in a B body tank which solved a few issues. 1. mini tubbed car exhaust issue. 2. Big enough tank without putting a fuel cell in a mini tubbed car. (I think it was a fastback so not compromising the fold down) 3. Had the correct "slope" that it did not hang down below the rear valance.....

I have looked as I do not wish to clog up the forum with unnecessary chatter, but I cannot find this member for the life of me. I wish to know ....1. was it actually a B body tank that worked? 2. Are you running EFI and if so, where did you source the tank?

Thanks in advance, I know I saw it somewhere, I should have made a note of it.

AH HA! I knew I had seen it somewhere.
[FOR SALE] - new TANKS inc. gas tank for A-body 3" tailpipes

So I went ahead and got a B body tank to see if this sellers claim was true. It was a tight fit....too tight. I felt like I was just making a pinto out of my car it was up against the rear metal just in front of the bumper. It also was hitting the diff. The fill hole was too far forward although it could have been workable. Any way I bought a tank (not a cheap tank mind you... i committed with a efi Tanks inc one.....I need my head examined) and cut off the *** end and am in the process of welding it back together and using pontiac gto straps I had laying around to secure. BAM! Wish me luck.

Ok so got the tank welded back up....It aint pretty, but except for a few pinholes.....she is a runner! So my question to the tank seal m up gurus is........Out of all the products out there that seal gas tanks, which is the most recommended for clean , never been run, no rust tank? Por 15? the eastwood sealer? northern fuel tank liner? probably need to put some etcher in there. This is an EFI tank if it matters.

Thanks in advance, I have never used tank sealer before.

Dont see this on the "new post" or "recent post" so Im bumping to see if I can get any action. Has anyone used tank sealer? Any luck? How old was the tank? rusty?
Thanks FABO!

They all need tooth to adhere. Never been fond of them. Caswell is the thickest I've used for sealing pin holes but does not adhere to rust like por-15 or KBS coatings. These are the 3 i have used. KBS and POR-15 are virtually the same but KBS has WAY better customer service. I dont know how you are going to seal up that tank with all of that new galvanization in there. Galvanized coating is one of the hardest things to successfully coat.
They suggest using drywall screws to beat around in there to create a profile for adhesion. Whatever. I really don't know the answer but just sharing what I have done on a few motorcycle tanks. The KBS and POR-15 worked great on those rusty tanks. I did a test on rust with all of them and the Caswell coating peeled off of the rust. The POR and KBS adheres well. Really well.

I have a B-body tank out of a ‘68 charger in my Duster, been a couple months now. I saw the same post as you, and I exchanged a few emails with that member. I’m still not sure what he did to make it fit, because having done it nothing short of major surgery will get it done and his description of what he did just won’t work.

I cut out the center of the rear crossmember, kicked it back almost 3”, and replaced it with a section of 14gauge I had bent up on a buddy’s brake to do it. I moved the triangular braces too, as they were also in the way. I actually swapped them side for side and welded them back on because it flipped the tabs out of the way of the tank. There’s no way to make that tank fit otherwise. With the tank moved back so it clears the diff the tank fill is pretty much in the right place, close enough to use the stock filler neck anyway.

As far as the tank sealer does, good luck. I’ve had very little long term success with tank sealers. My plan is to use an EFI tank in mine too, which is a big part of why I didn’t modify the tank even though my current tank is just an $80 stock replacement tank from Amazon. All those fine particle EFI fuel filters will not be a good combo with the sealer. Not from anything I’ve seen. The sealers work fine for awhile, then at some point the sealer fails and feeds itself into your fuel lines, filters, carb etc. All the additives in modern fuels don’t help, and the fact that they change those additives all the time now pretty much guarantees a sealer won’t be a long term solution. Even if it works great now couple years from now the fuel blend will change and that’ll be it.

The other reason I didn’t go after the tank is I wanted a 19 gallon tank. Or more specifically, I didn’t want to take a stock 16 gallon tank and then lose even more capacity with an in tank pump.

Ok Thanks for that. Ill post what I do. I may try a 219ish loc tight wicking thread sealer with a little heat. These pinholes are really only showing themselves with pressure in the tank. I like the warning about the galvinization of the inside of the tank and I will keep that one in mind for sure. As far as time until failure of seal because of ethanol and such....all good information. Wish me luck, maybe Ill chase down those pinholes with the welder after all and then prime/paint. Ill watch for leak and if it does at least ill know what it is.

Thank you for your replies

Look up aircraft fuel tank sealer. Should work .