Questions about feeding my 415 6-pak

[WayneT]

Well I thought I had the carbs setup pretty good until last evening. When I would try some WOT runs the engine would pull strong to about 4000 rpm and then it would fall flat like I let off the gas completely. This has not happened before. I'm thinking the carbs were running out of fuel. Now some background. I'm running 5/16" pickup and fuel line all the way to the carbs. I was thinking I would have to step up to 3/8" but the 5/16" has worked ok until now. Also running a stock replacement fuel pump. Should I be running a 120gph pump? Anyone know what a stock pump flows?
Also, all my tuning up to this point has been done in 60* temperatures. Yesterday it was 88* and the engine was running hotter than it has been while I did all my tuning. Would higher temps cause this or make the problem worse?

[dwc43]

Higher temps always reduces hp due to the less dense air charge. You could be having a fuel problem with the heat or just a bad pump. I'd replace the pump with a new CArter pump.

[dave571]

88' isn't that hot. You could be getting carb perculation, but I doubt it.

Personally, I think the 5/16" line is way to small for a 6 pack on a motor that big.

I would step up the line and the pump (.02)

If you go to an electric pump, there will be less tendancy for perculation, and increased fuel delivery.

[Crank]

5/16 is to small you have to think of your set up like a big block more cubes more fuel ,bigger carb ,

[pishta]

I agree on the fuel volume issue. Imagine 3 carb bowls filling up at once off the same supply line, you get your bowls drained fast with the cubes you runs and then have the same 5/16 line trying to fill all of them at once. Either a higher volume fuel pump or a larger supply line. You would think you would need a 50% larger volume pump for a 6 pack from a 4bbl, dont know what they were from the factory.