what is this part called..

[Mustang30240]

not the filler neck, but the rubber piece

View attachment 375069

 

[Busted07]

That would be the gas tank tube insertion hole rubber thingy.

I have no damn clue man, i would just call and ask them for the grommet that goes around the filler neck

 

[wythors]

I would call that a "fuel filler neck grommet" or a "fuel filler neck shield".

 

[85_SS_302_Coupe]

Flux Capacitor

 

[speedfreak98r]

Johnson rod?

 

[Blakthorn]

leaking gas?

 

[cenok is family]

prophylactic?

 

[Ozz]

filler neck condom

The Ford manual points to that and says "Mounting surface", but labels the whole neck assembly #9034 if that might end up helping you any. I'd just look for a Mustang being parted out or hit up a junkyard and grab that piece and/or neck. good luck