Vapor Lock

I am looking for HELP my 69 Mach a 428 car is giving me a fit with Vapor Lock.  In slow driving, stop and go traffic and at drive away after a stop of 15 to 30 min. I have changed the pump, and wrapped the fuel line pump to carb and installed a 3/8" thick carb gasket with NO improvement.  

One suggestion - pull the intake (if the 428 has a stock iron intake, best get a hoist LOL) and block the exhaust crossovers.  If it's an aluminum intake, especially do that.  If it has a stock Ford aluminum spacer under the carb, replace it with a Moroso 4 hole plastic model with a metal heat shield under it.If you're not up to pulling the intake, you'll need at least a heat shield - preferably under the spacer.  You may have to modify the shield for PCV operation.

If you don't drive the car much, you might just have a problem with the fuel - the specifications change with the seasons.  Google on "gasoline Reid Vapor Pressure".  
1967 Falcon 4 door 351C-4V
1970 Mustang 351C-2V
http://raceabilene.com/kelly/hotrod
Owner built, owner abused.

This "new" gas is crap for older carbed cars. Look around and see if you can find GAS. Bythat I mean look at the gas pump. If it says 10% ethenol, don't use it. Around here in Athens Ohio, all we have is Valero gas that so far dosent have that crap in it.Otherwise, Get a 1" phenolic spacer Which will also give you some needed torque, and maybe a "cool can" to cool the gas down.  

i too have been having fits with winter fuels...   75 E250 with a 460 and a 4350 carb...   the fuel just boils in the carb.. makes it almost impossible to drive...  i also have had to change the fuel filters to prevent some of the vapor lock at the fuel pump... any restriction and it will stall when really warm...  a shot of cold water over the fuel pump will help get it started... i am almost ready to replumb the fuel lines and go to a later fuel pump with 3 lines... on suction.. one return, one to the carb... with the return system... the fuel pump vapor lock problems are removed as the fuel is circulating constantly...

do you have a cold air intake kit on your motor..???? so the carb is not getting hot air from under the hood..????

i have also seen an aluminum heat shield to go under the carb... that blocks the radiant heat under both float bowls..  see if you can get the guys at the local parts store to pull the bin boxes of carb base gaskets and start digging through... the heat shields came on 83 -84 mustang 5.0 HO's with a holley 4 bbl carb...   i have also seen the phenolic spacers with extended areas on both ends and releifs for the holley accelerator pumps... if you are running a holley carb... if you are running a motorcraft  well thats another question...

i have started dumping even more octane booster and that helped a tiny ***

hopefully... this tiny bit of info will help...

i wish that i could get some of that ethanol free gasoline around here..

i wonder if the ethanol production for gasoline is a conspiracy to get cheep sources of high fructose corn syrup for the marketers of that sweet stuff... it is a by product of ethanol production...  

First off vapor lock occurs in a fuel pump not in a carburetor. There are two different problems. Vapor lock occurs when the fuel pump suction side exceeds vapor pressure of the fuel and the fuel turns to vapor then the pump cannot pump because it has only vapor which cannot be pumped by the typical fuel pump,,,thus vapor lock.
What occurs in a carb is fuel percolation and evaporation. Usually this manifests itself in bad idle and hard restarts in hot temperature.
The cures above are good, at Ford we sometimes used a foam block around the fuel pump to insulate it from engine heat. In a car like a 428 mustang this is a serious problem because there isnt much room. Its also true that a phenolic spacer or heat shield will help. The cure is cool air and isolation of the carb from the manifold. Ethanol itself while it can be troublesome because of its hygrospic nature(collects water) is probably not the culprit since vapor pressures are set by State law and include the fuel as mixed. Problems with seldom used cars occur when a car loaded with fuel from a winter source is driven in a hotter climate thus encouraging vapor lock since the fuel is more likely to vaporize then summer fuels which are formulated for hotter driving conditions. If your actually experiencing vapor lock then concentrate on the fuel pump and inlet line, anything that transfers heat to the pump. If its idle and restart problems then concentrate on isolating the carb itself.