Aftermarket Gas Tank Outlet Threads - Which One?

[hi_volt]

I have a new gas tank for my 47 Plymouth that I bought from Mopar Pro and am planning on using a hose barb adapter at the fuel outlet in conjunction with flexible hose to connect to the steel fuel line.  I'm trying to determine what thread pitch the fuel outlet is on the new tank.  I found two threads on the forum that discuss the Mopar Pro tank threads.  One thread says to use a 1/2-20 straight thread barb adapter (like a Dorman 785-402D) and the other one says to use a 1/4 NPT tapered thread barb adapter (like a Dorman 785-414D).  Does anyone else have experience with this tank and can offer their input?  Thanks!

 

Gas tank outlet barb fitting - P15-D24 Forum - P15-D24.com and Pilot-house.com

 

5/16" fuel line addapter 1/2"x20 - P15-D24 Forum - P15-D24.com and Pilot-house.com

[Plymouthy Adams]

surely the seller can answer that question for you.....

[Sam Buchanan]

Go to your local auto parts or hardware store and get a brass 1/4" NPT barb fitting and see if it fits your tank, I suspect it will. If it doesn't....go to Plan B. 

[Harley PHD]

My aftermarket tank had a bubble flair fitting on it like the original steel fuel line.

[hi_volt]

Update.  I went to my local O'Reilly Auto parts store and bought one each of the Dorman 785-402D (1/2-20 threads) and the 785-414D (1/4 NPT threads) fuel hose adapters.  The 1/4 NPT thread diameter is too large to screw into the fuel outlet on the new tank.  The 1/2-20 threads do fit and I can hand tighten the adapter most of the way down without too much effort.

 

I also noted that the female end of the rubber fuel hose that goes between the steel fuel line exiting under the radiator and the mechanical fuel pump also has 1/2-20 threads, so it makes sense to me that both sides of the steel fuel line would likely have the same male connector threads.

 

If I hear back from the seller, I'll post his response to my inquiry.

[Sam Buchanan]

Now the question is whether or not you will need the little brass ferrule found in the original tank to get whatever fitting you use to seal tightly. Straight threads usually need a flared fitting for sealing.

[clarkede]

I replaced my fuel tank with one from Mopar Pro back in 2020.  I also replaced the fuel lines with flexible lines and connectors.  I used two adapters at each end of the line (Russel 640330 - Adapter, INV FLR, Straight, -6(1/2"-20).  The flex line I used had additional adapters in it - 16FT of 6AN Nylon Braided PFTE Fuel Line Kit (See images)

[hi_volt]

Confirmed by supplier.  Threads are indeed 1/2-20 and the brass ferrule is needed.  Thanks for everyone's inputs.