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How about a repair to the threads using a Heli-Coil? They are available for 1/8 NPT.

they make a teflon tape for gas. its yellow and will solve your problem.

There's no thread sealer on the filter side so it's safe to assume none was used on carb side.
I'd disassemble the carb side and inspect to make sure there's no cracks or lost threads. Looks like a screen filter cap behind so you can see from both sides. If it's cut a face groove, if threads OK, I'd file off the face flat again. From the grooves on the brass, looks like a pair of channellocks or small pipe wrench was used, and over tightened.
I'd definitely get a new fitting, and don't spin on from one side. Tighten each side independently. Use a short flat wrench. Tightening the filter into position probably lead to over tightening the carb side. A union is best for this.
If the threads are messed up, this is probably cast aluminum and part would have to be replaced. A skilled TIG welder maybe able to fill so it can be retapped but would ruin the finish. There's some commercial type epoxy metal fillers but I don't recommend that approach long term. They're for emergency repairs.
Since dissimilar metals, use a thread sealer. I'd use a non-teflon thread sealer, aka "pipe dope". Teflon seems to work itself loose in vibrating services and tape extrudes out during tightening tapered threads so there's not much between the threads. Tape bits also seem to end up plugging carbs.
Make sure you don't over apply sealer, and wipe up the excess.
I'd stay away from brass pipe(nipples), as they can crack tightening with pipe wrench. The jaws dig in deep on soft material. Hand tighten or use soft jaw if U must.
Always check threads with a thread gauge.
Brass fittings are a pain any more as they've changed to lead "free", and they're just not the same and difficult to find some of the old configurations.
ps: I doubt, as most SAE gas line was tapered or flared, but there's a small chance the carb side had a special flare fitting with straight threads and someone jammed wrong fitting on. That would take some research and more info.
It'll be obvious on inspection. Always check threads with a thread gauge.

There is no Teflon or sealer of any type from the photo supplied. So our suggestion would be to start there. But more than likely the body of the carb is the issue from years of the fitting being removed and being over tightened. Unfortunately the idea of using a fiber washer or copper washer will not work as there is no seat or surface on the fitting (as seen in the photo attached) or carb body for it to sit flush so that it will seal. Same can be said for the idea of a helicoil. A conventional wire type can be prone to leakage especially with fluids that are thin like gasoline. So if threaded portion is damaged you would want to use a solid thread insert with sealer on the outer portion of the insert.

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In my journeyman prototype machinist days we used Heli-Coils all the time for pipe threads in soft material. Done properly, they will absolutely not leak and will probably outlast the rest of the car! However, on an odd casting shape like this, better to have a carburetor shop handle it as they have all the proper tools. I had several done locally by Ace Fuel Systems and never a drop after the repairs.

I would try the yellow teflon tape-not much cost. If the pot metal thirds have been expanded to far for tape I would start looking for a parts or core 531 with a good bool assembly (make sure the venturie are the same)

I spoke with Tim at Daytona, the source of this carburetor. This is common problem for them, caused as James described and not necessarily from overtightening.

He suggested replacing the fitting with one that has larger shoulders that will accept a soft washer. He also suggested judicious use of blue locktite on the threads. Fitting and washer is in the mail and I will let you guys know how it goes.

Thanks to all,
Mark

Just hit me that i had this problem about 10 years back on a fuel pump inlet so i went digging into my spares to c what i did. I used one of those sealing washers from McMasterCarr with a 1/4 male npt to a 1/4 female npt Fitting

https://www.mscdirect.com/product/details/83295626

Worked for me.

These are the fittings that Tim sent. Left side with washer to the carburetor. Used Loctite blue on threads. After 100 miles, no leak.

Thanks to all who shared ideas...
Mark

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