Fuel line fitting on SMTA

[BBinOk]

The fitting that screws into the carb an has flair fitting for fuel line on back side . I need to know what the thread is that goes into the carb. Rigging up new fuel setup on pulling tractor. Thanks

 

[rustyfarmall]

I think it is standard 1/2" fine thread. NOT pipe thread.

 

[Brian Schmidt]

The thread is 1/2"-20 compression tube seal.

 

[the tractor vet]

And why do you think you need to run a bigger fuel line to feed and M engine ?? I don't care if ya run a 2 inch line it will not help you one bit . since you probably never though about this BUT you can only flow so much fuel thru the needle and seat and it is a lot smaller then even a 5/16th's fuel line . I fed a built 609 cu in engine with a three inch in and out Bendix carb with a 3/8th's fuel line with and Elcheapo electric fuel pump with only 2 psi pressure and never starved it . Same with many dual quads run off a 3/8th's line running 6 psi . even if you ran a four bbl. carb with a same electric pump the neddle and seat will still only let so much fuel in the bowl and only so much will pass thru he jet of the carb., and here again you can only go so big on then .