One of the things I tried over and over was return vs. no return and not using a return seemed to be better for some reason.  With the rubber hose replacing the OE rail, I did not run a return line.  I looked through my files, but I don't have any pics of the new routing.  I will eventually take a few pics and post them.  I'm going out of town again for work, so it might be a week before I have time.

another approach if you're not using the mechanical pump: 

i re-routed the fuel lines to avoid the heat issue when i went to su's on my '78. i bent the supply line up 90 degrees and ran a rubber hose up the firewall, mounted a clear filter to the firewall above/to the right of the battery, then ran rubber line along the firewall to near the throttle linkage then across the carbs using a "T" at the back carb and dead-heading into the front carb. the rubber line between the carbs runs under the balance tube - just to be safe, i rolled a little heat shield for it out of some aluminum flashing because i could feel heat flowing up between the carbs - works fantastic, never had a problem all through the summer. i'm running a little airtex electric pump which seems to do just fine.

this re-rout eliminates the circuit around the head and doesn't have mounting points to anything hot.

Geoff, Do you have return lines on your set-up? I've always wondered if they were really necessary.

Was that question for me?  Either way, I do not run a return.  I tried it with and without and found no benefit to keeping it.  Before I eliminated the OE rail, it vapor-locked worse with the return.

I plan to do the fuel line rerouting behind the engine to bypass the fuel rail this weekend.   I'll try the no return line first as less connections is easier and then I don't have to find a way to create a reduced flow back like the stock rail.  

It is supposed to be decently warm on Monday so if it stays that way that should be a really good test for it.

When you dead head the fuel supply, be sure to plug the chassis return line to the tank so no fuel can puke out while driving.

my fuel line is dead-headed, and i removed the evap canister and plugged the return line.

 

 Oh how I love simplicity. You stripped it of ALL the extraneous B.S.