I'm being decisive on this one as far as intended usage Makes a change from the 10 year extra cab
No reason for something more than 31s for a non-hardcore wheeler. This will see extreme daily driving and hardcore log roads That and the occasional light duty towing.
If the S10 tank fits, I'd take a wild guess that a suburban tank would fit also Time to pull a tape measure out
If you end up going with a stock used tank, beware that there is a change in the tanks, so you might be limited to early tanks. I think dieselcruiserhead on the board discovered that late ones dont fit?
I would really be interested in getting a bigger tank, might be time to get a few made.
As for retaining the stock tire carrier, I dont think any extended range tank will allow for it, since the extra volume comes from using the area that the spare tire carrier occupies...
I'm not sure when the tank changes occurred but my '72 tank does not look like it'll bolt up to the '78. The mounting system is completely different. The '72 tank would have to be re-drilled because the bolt holes to the mounting points are different. The '72 mounts to the floor of the body and the '78 mounts to brackets that bolt to the frame.
Trollhole did you have to do any drilling for mount placements?