I've pretty much retired my bronco from mountain travel after stalling in Eisenhower tunnel 2 years back due to vapor lock issues . I wanted to post my fuel set up and see if i can get some input to help with my issue. I am running a holley 350 cfm carb with the built in filter removed . Inline fuel filter fills up fine ( glass filter about 1 foot from the carb) when cold after running for awhile the filter is almost empty and surges fuel , and fuel pressure gauge fluctuates and drops to around 3 or 4 psi . i have a carter electric fuel pump mounted under driver floor board on the frame with another glass filter before it which fills up completely through out . I also have the 23 gal rear fuel tank . Bronco doesn't actually stall in town but gets kinda jumpy at red lights.

Sounds like a perfect reason to go fuel injected :)

what he said ^^^^ is without a doubt the best option but, a heat shield under the carb, or phenolic spacer may easily cure your vapor lock woes. as well as shielding the fuel line.

x2 on the phenolic or wood spacer as a starting point. Check your fuel lines-are they near the exhaust?

Dual exhaust?

I have chased this problem a lot in my short time running my Bronco. Some of the things you may consider if you don't go EFI (I have decided I am done trying to chance the vapor lock and am going EFI this winter.)

- The Carter electric pump pushes fuel instead of pulling. It should be mounted as close to the fuel tank as possible.
- Make sure any fuel lines are as far from Exhaust as possible. This includes your headers. Also-- If you can run your lines as far away from your engine block prior to connecting to the carb, you will have a better chance of it not vaporizing so close to the carb.
- I have heard of people running a higher pressure fuel pump with a fuel pressure regulator closer to the carb. The higher the pressure in the line, the higher the boiling point would be (why EFI works so well.) I actually had a frankenstein experience with something like this in Moab this year. I was getting vapor lock on the one hot day we had where we were sitting and idling a lot. My mechanical pump was not doing the trick. Someone had a High Pressure pump as a spare and so we hooked that up pretty close to the fuel tank. I had it wired off of my headlight switch. Whenever it would start to stumble, I would hit the lights for about 3-5 seconds and the fuel pump would push right past the vapor and "re-prime" the line.

Hopefully you can find something that will work for you. I think EFI is the best way to go, but if that is not in the cards for you-- may want to try the above.

-Mike

i am running a phenolic spacer , i do have duel exhaust i am going back to the 2in 1 system though , not to the EFI point yet here are a few pics

Had a similar issue - ended up usinig a fuel pressure regulator with a return line. If your running one tank it 's a breeze to install if not get ready to wrangle fuel line.

If it helps I also wrapped my rubber fuel lines in insulation tape, have a spacer but also like a large aluminum plate between the carb and manifold. I also bored some 2" holes in the fender wells to help circulate/ vent more air.