71 roadrunner gas tank sending unit

[Kind B]

can someone tell me what size sending unit i need in my 71 340 roadrunner, is it 3/8 or 5/16, did small blocks take 5/16 inlet and big blocks take 3/8 or did it go by year, any help would be geat

 

[oldbee]

As far as I know, 5/16”. Hemi & 6-pak s got 3/8”.

 

[bee71]

5/16