Reply to "Fuel Tank Drain Plug Size"

Ron, only the PLUG is tappered. The bung is not!
The 22x1.5 adapter from Pegasis should work with no problem. Particularly with the o-ring.

That can probably be swapped for a copper gasket I'll bet.

Also point of noteworthiness: 1)1/2npt will physisically fit the factory tank bung as it exists.

2)The difference between the two is that the 1/2npt has a thread pitch of 1.75mm instead of 1.50mm.
I am tempted to just run a 1/2npt tap through it and use an o-ring adapter to seal it.

3)the location of the bung makes it very important to hold the fuel line as close to the tank as possible.

Although the the nice radius bend hose ends are signifigant to fuel flow I suppose, even with a 120 degree end the line is projected into harms way. A banjo or maybe one of Earls fancy flex-o-ring pipe to jic would be acceptable. Especially if it is just a return.

I was going to use this drain for a return line for the EFI.
Considering that I took 6 gallons out of the tank when I thought it was empty is a very poor reflection on my Holley Electric fuel pump. I knew I had fuel in the tank and had originally located the electric fuel pump in a way that it could be used to power drain the tank. I used it that way here until it ran dry. The only thing is that there were still 6 gallons in the tank. I think there is something wrong here?

This car is unreal. It is just a never ending sagga of twist upon twist. The term, of "opening a can of worns" really seems appropriate now.
Granted it isn't even an Italian fuel pump? Holley wasn't Italian...right?
Will it ever stop?

Well you never know? Who would of thought a guy named Weber was Italian?

Oh, Forest, you are right on with the 1/2npt fitting. The 1/2npt does screw in!
There is a difference in the thread pitches though. The 22mm plug is a 1.5 pitch and the 1/2npt is a 1.75 pitch.

It explains why you were able to install it tighly though.