1970 -6 Gas Tank Supply Pipe Hose Bead Question, Morphed into: “Does the OE fuel return system cool fuel going to engine?” uh … No Options

[Rufus]

Hi Folks - I have the entire fuel system out of 9140431482 back to the Webers for update, cleaning, etc. (Webers already reinstalled after thorough cleaning.) The gas tank fuel outlet pipe has no hose bead.

Is this normal? Seems odd there wouldn’t be one.

Thanks,
Bob

[technicalninja]

IMHO putting the return back in will increase fuel temp; not reduce it.

This is correct for FI cars. Carbed stuff not so much. Increasing pressure on anything gaseous or liquid increases its temperature. 60 psi is definitely a heat creator.
3.5 psi, not so much. I bet it would be hard to see a temp difference.

Being back in the engine compartment for any length of time will heat the fuel and a return would help. A "cool can" would help as well.

I'm a huge believer in moving the pump to underneath the tank. Brant is spot on but...

This is a real 6. I'd be loath to make any changes over stock and I'd make DAMN sure that any changes I made could be easily changed back to stock without any evidence left behind.

The fuel return for FI cars went through multiple changes over the decades.
The increase in tank temps increases evaporative emission badly enough that Mercedes actually routed the AC low side suction line through a fuel cooler. This is bad- assed and I'd have had that cooler on the inlet side to cool the fuel before it hit the injectors.
Mercedes put it in the return line just to cool the fuel returning to the tank.

Modern shit mostly has the pump and the fuel pressure regulator in the tank and this system is labeled "dead head" as all the fuel going to the engine will be consumed.

All of these scenarios are trying to keep the fuel in the tank as cool as possible for emission reasons.
It's not for the betterment of the engine...