Too much pressure in the gas line...spitting?

[pauls340]

Just replaced the fuel filler tube gaskets and seal on the Demon. The next day I started the car, stock 340 with Holley single feed 650 Spreadbore, stock fuel pump, backed out of garage and then back in, only to find three pools of fuel on the drive, about 5" dia. I discovered the fuel line going into the stock fuel filter was leaking, when i pulled the fuel line out of the rubber hose, the pressure was spitting fuel. Could the non-venting OEM 71 gas cap cause pressure buildup? thanks

 

[67Dart273]

A fuel filter/ line connection that's leaking IS NOT CAUSED by the pressure from a cap. Your pump develops a LOT more. If you put more than the 6 psi or so developed by a pump into a gas tank, it would deform and possibly rupture

So the leaking fitting was just --a poorly made/ clamped fitting.

So far as pressure in the tank, I'd look around the various smog fittings, and see if there's one you can dedicate to a "no pressure" tank vent.

Either that or install a vent just like the "pre evaporative" tanks had-- a fitting on the high end of the filler tube, goes up in an inverted U to the top of the trunk, then down along the backside of the filler tube and down through the trunk floor. The tube "dead ends" (open) INSIDE the rear frame rail.

This MUST be sealed from the trunk interior.

A diagram representing the 67 vent