Vapor lock and or fuel boiling due to the fuel in todays market boils at a much lower point. My fuel line was so hot your could not even touch it for more than a second. Here's what I have found at this point and the thing I have done.
1. Rebuild the carburetor (helped lower the temp of the fuel line but did not totally fix the problem), Purchased the carb kit from Mikes carburetor. Watch his video's on line.
2. Check the radiator for proper operation. I found mine was circulating but had a lot of blocked tubes due to age. replace the radiator more consistent operating temperature.
3. I installed a phenolic riser insulator raising the carburetor 3/8 of an inch. They also come in 1/2 depending on your clearance. (purchased on Ebay)
All three of these really helped but still not a 100 % fix. So after searching all over the internet and speaking with life long Ford mechanics I ran across you tube videos on vapor lock. I found that in the 60's and the 70's that Ford, Dodge, Plymouth and other used a vapor separator in the fuel line just after the mechanical fuel pump. This returns the access fuel and vapor to the fuel tank allowing a Constance flow of fuel preventing over heating of the fuel. These cars came with a return line to the fuel tank from the factory. This is the same as today with fuel injection has return lines to the fuel tank. This all made since to me so I saw a video of a guy drilling a hole in the sending unit and JB welding it in (not sure I wanted to do that) fixed his problem 100%. So I went on the hunt and found the WIX 33041 vapor separator. I also found out the Ford used three different ones. They had .04, .06, and .08 orifices. The Wix 33041 has a .06 orifice in it and was used on 70 chevys. I also read about electric fuel pumps electric fans but this made the more since to me. I found on EBAY a fuel sending unit for 64 - 68 Mustangs with a 1/4 inch return line built in with a check ball only allowing fuel and vapor to return to the tank sold by MCM products. They also sell them on Summit racing but are twice the price. I also ordered 1/4 aluminum fuel line from Speedway racing parts and the filter from O'reilly auto parts.
Fuel sending unit 39.50
Vapor Separator 8.00
Fuel line 15.00
I will be installing this this coming Tuesday when my buddy's lift is free. I have 100% confidence this will be the cure!!