Fighting Vapor Lock
Among the theories to minimize or eliminate vapor lock includes: A. insulate the fuel pump; B. Insulate the fuel line inside the engine compartment; C. Add a "return line filter" (GM style) and run a return line back to the fuel tank; D. Add an electric fuel pump back at the fuel tank to assist "clearing out" the fuel system before starting or operate the electric pump all the time. So here is the sequence of the "fixes" in the order of "easiness" and minimal cost. I insulated the mechanical fuel pump the best I could with a starter insulation kit. Ugly, but....well, that didn't work.
This is the connection of the 1/4" fuel line back at the tank. Drilled a 1/4" hole in steel neck and used JB Weld Qwik to epoxy a short piece of 1/4" O.D. tubing into the filler neck. You can also see the fuel filler neck drain line to under the car, just in case of spillage inside the filler box. (See "Replacing the fuel filler with a door type" gallery. - go back to the top of the page and click on the little house icon in the upper left of the screen.)
Another thing to do is to do what you can to keep the temperature down under the hood. I bought a probe type controller for the radiator fans. Before I installed this control, the "Chinese" Block mounted switch switched the fans on at about 200 degrees... but after about a month, the switch was closing at 220 degrees, contributing to the vapor lock problem. This control is adjustable and easily accessed, so I abandoned the block mounted control and installed this one. There was nowhere at all to mount the probe inside the radiator, so I loosened the radiator bracket at the top, pried it up a little, inserted a piece of "underhood insulation foam", then stuck the probe in between the foam and top of the radiator. Will be adding a protective sleeve for the probe line.
If this doesn't work, I may have a car for sale. That is a joke. SOOO , I got a Carter P4070 fuel pump. 4.5 amp. and also a Carter 1691002 check valve. This assembly will be installed after the primary filter that is about half way between the fuel tank and the engine on the outside of the frame rail on the passenger side. Fuel comes in from the left fitting, through the check valve, through the second fitting, and on to the mechanical fuel pump when the electric pump is not operating. A push button switch on the dash turns on the pump, which pulls gas from the left fitting and then back to the fitting on the right, and the check valve closes, so full pressure pushes fresh, cool gas through the mechanical pump to the secondary filter and back to the fuel tank. Had to mount the pump back under the trunk next to the fuel tank, but it took 12 feet of 3/8" fuel line to divert the fuel to the pump. THIS WORKS LIKE A CHAMP, (UPDATE ! ! ) except that it did not solve the problem of "refusing to start" when the engine bay has sat there "soaking up heat". Finally found that I had one of MANY HEI ignition modules that simply quit working with elevated heat. So, scroll down for the ultimate fix....!
I finally learned from scanning many websites and doing searches on "HEI ignition failure due to heat". What I learned is that "many" stock HEI ignition control modules will simply QUIT WORKING with elevated temperatures, but then as soon as they cool down sufficiently, start working again. Replacement with this aftermarket module (MSD "HEAT" module, available at Summit or Jegs and direct from the manufacturer for the same price) cures that issue. One warning: it "barely fits" inside the HEI body, and takes some manipulation and patience to make that little grommet and wiring to go in.
VIDEO !...Thought I'd throw this one in. If you look closely, you can see the "green" printed circuit board through the transparent distributor cap just below the horizontal ignition wire on the lower right. Click on the picture for the video... I thought it'd be cute to add a few LED lights inside the cap that were left over from the lighting strips from the hood/trunk lid interior lighting. The blue masking tape was for labeling the wires ..I have since removed the labels..ahahah