Larger capacity Gas replacement tank.
 

I'm looking to upgrade to a higher capacity Gas - fuel tank. My current tank is in the mid-20 gal range. I'd like to increase that to 40+ gal range.
And, utilize the existing truck cavity.
I can't use a bed mounted auxiliary tank. Because, I have a bed-mounted Lance camper.
The research I've done only shows replacement tanks specifically called out for diesel trucks.

Any suggestions?

'02, 2500HD, 8.1L, 4x4, Allison, crew cab, LS
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