LS swap gas tank pressurizing

[1976dully]

I've got a 5.3 in my 76 C30. We replaced the entire fuel system with a new tank, two port tank insert, an inline pump, and a corvette fuel filter/regulator.
Truck starts and runs fine, but the tank pressurized.
Would a vented cap fix this, or do I need to do something different? If the cap is the answer, which one should I get? I'm not having any luck finding one that will fit.

 

[Ricko1966]

I've got a 5.3 in my 76 C30. We replaced the entire fuel system with a new tank, two port tank insert, an inline pump, and a corvette fuel filter/regulator.
Truck starts and runs fine, but the tank pressurized.
Would a vented cap fix this, or do I need to do something different? If the cap is the answer, which one should I get? I'm not having any luck finding one that will fit.

The tank has to vent some how if you a 2 port and you are using one as supply and one as return you need to create a vent somehow. Vented cap is probably the easiest at this point. So other know you need a three port sending unit.

 

[TotalyHucked]

^This. If you end up having issues with fuel sloshing out, you'll need to change to a 3 port and run a vent line to the back of the truck

 

[1976dully]

The tank has to vent some how if you a 2 port and you are using one as supply and one as return you need to create a vent somehow. Vented cap is probably the easiest at this point. So other know you need a three port sending unit.

Hindsight being 20-20, I should have gotten the 3 port. I've never had an LS swapped anything before.
I've even thought about installing a vent in the filler neck.

 

[TotalyHucked]

Just a heads up, inline pumps often die a quick death. It's more work but if that happens, I'd highly suggest swapping over to an in-tank setup. An '87 fuel injection tank, sending unit (which will be 3 port), a Walboro 255 or similar in-tank pump and a Corvette regulator is pretty much the go-to, reliable setup for LS swapped trucks. That's what I run in mine and it's been great for 60k miles now. In-tank pumps get cooled by the fuel, so they live much longer and it's quieter

 

[1976dully]

Just a heads up, inline pumps often die a quick death. It's more work but if that happens, I'd highly suggest swapping over to an in-tank setup. An '87 fuel injection tank, sending unit (which will be 3 port), a Walboro 255 or similar in-tank pump and a Corvette regulator is pretty much the go-to, reliable setup for LS swapped trucks. That's what I run in mine and it's been great for 60k miles now. In-tank pumps get cooled by the fuel, so they live much longer and it's quieter

Man, I wish I had asked here first! I'll probably end up going that route. THANKS