EightSparks

iTrader: (3)

Well, I never made it public because I wasn't sure how well the swap would go, but almost finished putting back together my '79 Firebird with LT1/TH350. The car is now running, but one of the issues is the fact that I don't think that the fuel tank is getting a sufficient amout of ventilation, here's my setup:

-Stock fuel tank
-Walbro 255 inline pump, 2 inline fuel filters (Purolator F33144)
-Feed: -6AN line from tank to filter/filter to fuel rails
-Russell GM quick disconnect fittings on feed/return sides of rails
-Return: -6AN to 5/16 rubber hose to 1/4" tube on stock sending unit (for EVAP)
-EVAP: 5/16 tube (remote from the sending unit, stock location) to stock EVAP tube/no charcoal canister yet

The issue is that the tank has been sitting empty for about a year. It has been cleaned to the best of our ability. We put 3 gallons of fuel in it and after it sat for a while we started hearing popping (like the tank was expanding).

I don't know if its getting back into shape after being empty for so long, or the vapors are making it expand due to insufficient ventilation.

The cap does hiss after taking it off after the fuel has been in it for a little while (It never done that with the carbed 350). The tank doesn't appear to be swollen, but we had the cap on it for about 30 mins.

I just don't want it to go boom, so if anyone has had similar issues, I'd appreciate any suggestions/feedback. If I have to drill another hole in it, I will.

I know that this is LS section, but I'm sure that for this issue it doesn't make any difference.