vapor lock

[jviator]

I have a 79 k20 with a brand new 350 in it but it still has the original rochester 4 barrel carberetor on it. today my truck ran for hours in the city in 100 degree weather. I was almost home and i stopped for a second to get parts. when I started my truck back up i put it in gear and rolled a couple of feet and it shut off. it did that a couple of more times and then it was able to get me home. I tried driving it again about a half hour later and it did the same thing. Ive been told it sounds like vapor lock. Can anybody help me figure this out and know how to fix it. I do live in denver colorado if that helps