i think i have a vapor lock problem with my 68' 440/727, i have holley 750 vac. sec., with headers, once the car runs , i ran down the street about 3miles and back to the house, the car was idling in my driveway and went dead, wld not start, getting fire however was not getting gas, i thought was a fuel pump, when and bought new fuel pump, when the car dies, the see thru fuel filter has bubbles in it and is not full, once the car cools down for about 5 to mins will crank and run fine tell heated up again, then the fuel filter almost empty and bubbles, i have a 3/8 rubber hose feeding the carb, the only thing i have changed is i switched around the inlet to the back to get the inlet connection away from the dist., i have included a pic. of the set up that i am having the problem with, i was just going to switch it back around, but i thought i wld ask to see if i may have another problem.
thanks
Randy

this pic is after the engine has set for about 2 to 3hours, see the fuel filter is full, however once it heats up, the fuel filter gets empty and bubbles

loosen your gas cap to make sure you don't have a vacuum lock instead of vapor lock. I was having the same trouble. First trip today without the locking gas cap, and the car drove normal after a 40 minute trip. I still need to do more testing, but it looks promising so far.

i am using the 43year original, how do i check this?

for a test, you can just loosen it. When it starts running crappy and the filter is nearly empty, walk back and loosen the cap. If there was a vacuum lock in the tank, loosening the cap should let it breathe and the filter should fill up again and the idle should smooth out.

i will give this a try tommorrow, i have fat lady across the street theat calls the cops when i crank up the 440 after 9pm.

Not to be picky here but I would get rid of the rubber fuel line and glass fuel filter before you have a fire! You can get a really decent steel line made for little $$$.

Also ensure that the float level is set correctly and the fuel line is routed away from the headers/exhaust. If there is not enough fuel in the carb bowls it will boil out. Also, if the fuel pump is weak you can have problems similar to what you describe.

Flip the hard fuel line at the carb bowls so the inlet is facing the front of the car.

i agree about the rubber gas line, i have not really had the car on the road yet, the rubber line was the easy way out to get the car running,
i have already thought about the rubber line

i just put a brand new fuel pump, i thought it was the fuel pump to begin with.

i have also checked the fuel levels, they were both fine

do you think that by swapping the inlet to the back of the carb has made this problem?

It could but cannot say for sure but flipping it to the front will reduce the length of rubber hose which is a good idea along with getting rid of that glass filter. That long hose laying against the valve cover just increases the chances of heating the fuel even more. Flip the line to the front, change the filter, and keep the fuel line from laying on any heat source and that should be a good place to start.

Will the inlet to the fuel rail hit the distributor if you point it forward? I am pretty sure you will have to bend it slightly towards the driver's side to make it work like that. 'Just a thought...

now that you mention that I seem to remember that same issue on friends car several years ago and the end of that barb needs "tweaked" a little to clear the distribtor.

Get it away from the valve cover.

I don't understand why some flip that line, all your doing is making more area for the fuel to get in, it will clear the dist. if you set it up right, its harder running the holley dual inlet line with low profile intakes, i'm sure you can figure something out, i would too get rid of the glass filter, you more then likely have issues in the tank with blockage or in the factory lines, your starveing the fuel pump, i had this happen once, how you can check it (how i ckecked mine) is i pulled off the line from the inlet side of the pump, then install a short hardline & about 2 ft. or so of hose & blew the line to see how hard is was to push all the fuel back in the tank, thats when i realized it was badly clogged, just something to try if the gas cap trick doesn't work.

what kind of filter do you suggest?

so when i blow on the line, should i not have any
resistance, should i not notice any resistance?