Fuel Tank Size?

[Jon87V20]

I'm going to replace the fuel tank on my '87 Suburban V20 but since I don't fill it up all the way very often, I can't remember how much it holds. I feel like it was 31 gallons, but the measurements don't make sense for that.

My tank measures 34 3/4" X 28 1/8" X 12 1/2" (for the height, it was hard to get this one exact).

However, looking online, the closest size to that seems to be 35" X 28 3/4" X 13 1/8" which is supposed to be 40 gallons.

Can anyone tell me what I need to get? Should it be the 40 gallon with those measurements? Can you run a smaller tank like the 31 gallon without any modifications if you wanted to?

[Jon87V20]

Also, I was measure all the way out at the flanges where the tank is technically widest and longest. Should I not be measuring out that far and just keeping it tight up against the tank? I'm not sure what the proper way to measure them is.

[VileZambonie]

25, 31 or 40 gallon. Just make sure you are using the correct sender and straps for the tank you decide to run. Bigger capacity is better if you ask me.

[Jon87V20]

Thanks, Vile. I decided to just clean up the tank I have and paint it. It should be fine. It sounds like there's some tiny rocks or something rolling around in there. Hopefully I can vacuum that stuff out and have it all put back together for the snow storm we have coming this weekend.   

[Mike81K10]

Got the tank sizes and the new tanks are around $150 and the price might make it worth just buying a new one if you have to do repairs on an old one.

[Jon87V20]

Cool thanks, Mike!