Almost all new cars in the last several years have gone to a dead head system. The end result is cooler fuel, particularly as the fuel tank gets low.
I'm not sure how running the fuel through the rail, picking up engine heat (rails are always hot after extended driving unless your intake is composite material) and back to the surge tank will make it cooler.
Doing some fuel consumption math, at 60mph and 20mpg, a gallon of fuel should be consumed every 20 minutes, a quart every 5 minutes. So the volume of fuel in my lines and surge tank should be far less than a quart. The fuel in the lines should be replaced with cool fuel from the tank every minute or two. It simply shouldn't be enough time to vapor lock, as my fuel consumption should be even quicker since I am driving faster than 60mph and getting 20mpg, and the surge tank fuel should be replaced constantly with unrestricted flow from the gas tank. Yet here I am I suppose... My Skylark returns hot fuel from the rails back to the surge tank just like this set up, and it's surge tank is under the hood, subjected to under hood temps on top of engine heated fuel rail fuel, and it doesn't have this problem. Uses the same high pressure fuel pump and exposed to more heat under the hood.
I have a motorcycle oil cooler on the shelf I eyeballed yesterday and thought about plumbing in, lol. Instead I welded cooling fins to the side of the tank.
**I forgot to answer about the cam. The cam is now set to an honest 4º advanced from stock. I am considering backing it down to stock. This is assuming it was ground correctly, which I forgot to check. D'oh!
Edited by TheSilverBuick (07/21/1410:11 AM)
Rebuilding an OHC Pontiac 250 with EFI and a Turbo