Anyone seen these big tanks on a C30?

[IDtag]

Started some basic clean up on a 1982 C30 I bought yesterday. Really didn't have much time to crawl around under it before we loaded and started pulling the old diamond plate today. Found what are obviously aftermarket fabricated steel fuel tanks and they are huge. They run from just in front of the rear wheels to about the middle of the front seat... same on both sides. Anyone seen these before, I'm really curious what the capacity is.

My plan is to lower the truck so maybe paint them or hide them with a painted panel? The bottom of the tank is right about even with the frame but obviously a lot lower at the rockers. They seem to be pretty heavy steel so probably durable but really exposed.

 

[75gmck25]

When I first got my ‘75 K25 it had a dealer made, dealer installed auxiliary tank. It fit in about the same place as a stock saddle tank, but was made of welded together flat plates, so no rounded corners.

One convenience it had was a drain petcock in the bottom. You could open it up and fill a gas can from the saddle tank, or just use it to drain the tank. ‘75’s did not have a gas filler door, so they had apparently just drilled a hole for the filler in the right place on the side of the bed.

 

[Doppleganger]

I remember back in the day, JC Whitney had aftermarket tanks that went as big as dual 40s. No idea how they fit them in where the original 20s were.

 

[fast 99]

Might have been from a co called Travel Tanks. Had a set on 72 K20. Common before emissions and liability took over.

 

[bucket]

I remember back in the day, JC Whitney had aftermarket tanks that went as big as dual 40s. No idea how they fit them in where the original 20s were.

I remember those. I think they were sold all the way through the late 90's.

 

[Grit dog]

Similar to the aftermarket aux tank on my 77c10 that I just got. But mine is approx 22gal. Your truck being a crew cab is much larger capacity.
Mine is complete with a shoddy hole in the bed and poor fitment of the filler neck/cap.