454 Engine feels like its running out of gas

[Rickf1985]

It is not pressure that fills the bowl but volume. Three lbs. is too little though. the specs. are 3.5 to 5. And that is all assuming you have good volume at the specified pressure.

[kansascat]

 Thought id share a update on my rig. We went on a 500 mile round trip over the holiday weekend and was pulling the car trailer with both my jeep and my sons bronco II on it down to southern oklahome to go off roading. Anyway the outside temps got up to about 90 and there are a few decent hills we had to climb. It ran real well the entire trip as long as i was on the aux tank, located behind drivers seat on frame, but would only run for a half hour or so on the rear main tank before vapor locking and trying to die. I feel this pretty much rules out it being a ignition issue as that wouldnt care which fuel tank it was using. The carb boiling and trying to die on either tank seemed to be fixed tho now. All i did to it before this trip was i added a second thick carb base gasket to help insulate the carb from the intakes heat, and i removed the vacuum lines that control the heat riser pod on the manifold and the air intake flapper in the air cleaner, and advanced the timing some since back to home elevation.
Im still pretty convinced my rear fuel tank issues are related to the exhaust being run so close to it for such a long distance, and aggravated by it having a few leaks from thin spots. The fuel line is quiet hot to the touch after having been run for a distance. Perhaps the alcohol fuels make it even worse, i dunno. Either way its going to get a new exhaust that runs down the left rail only so its not near the fuel line any more, and im upgrading it at the same time as the first step in my quest  to find more ponies in the 454 for when we are in the mountains. My new set of headman headers arrived tuesday. I plan to have them buid a Y pipe to bring the two sides together just ahead of a new muffler, or get a 2 inlet muffler to bring both banks into with like a 3" outlet turned out the left side ahead of the rear axle. While im not a huge fan of headers due to the increased heat around the engine, especially the starter and plug wires, ill just have to make sure everything is well shielded and wires held up away as best i can. Next will be a cam intake and carb set from edelbrock. Once i have the new exhaust on it, i will try bypassing the mid point elec fuel pump, but i think ill keep the in line pump back by the rear tank to help push fuel to the main pump on the engine.

[Rickf1985]

That is a hell of a load to be pulling behind you. All things considered I think you have the problem pretty much narrowed down. With the headers you will have less back pressure so there will be less flow back through the intake as a bonus, the problem is that the heads were designed for exhaust to get to the EGR valve so there will always be some there until you go to a Non-EGR manifold. I never paid attention to what size yours is but if you have a frame extension you better be sure it is very well reinforced at the extension joints. These were always a weak point.