[jgpnashville]

Good news all around. The PO of my 67 K15 did a true dual exhaust sometime before it was parked in the early 2000s, so I have plenty of exhaust flow. I made the newbie mistake of assuming the idle mixture screws on the Holley 500 were factory set, as it idled well when first installed, but they were darn near screwed shut. After screwing them in and backing out 1.5 turns for an initial set, the engine idles well. I adjusted with a vacuum gauge on the manifold vacuum line for maximum vacuum and although the gauge needle wiggles quite a bit at idle, the truck is running better than it ever has.
After taking it out for about a 10 mile drive yesterday, she died pulling into a parking lot and wouldn't restart until it cooled down. I believe I have a vapor lock issue, as I'm running the OE mechanical fuel pump with the section of steel line to the carb that runs under the water manifold inlet. I also have an inline clear filter right below the fuel pump inlet and I didn't see much fuel in the filter. Still has the gravity fed in-cab gas tank as well. At first I thought the fuel pump was to blame, but now I think I just had a vapor lock condition.
I was thinking about changing the steel line from the fuel pump to a section of flexible line and maybe routing it over the water manifold to see if this will fix the vapor lock issue. I have also consider going to a universal-style electric fuel pump, where its tied into the oil pressure switch to cutoff, but I'm trying to take baby steps and not re-work everything related to fuel all at once.
Thoughts?