I just got back from my first long trip in my 80, that included a stretch of about 115 miles off the pavement. The truck performed great, with one exception, it has no range. I can get at best (on the highway) 130 miles out of a tank of gas. I took a couple of gas cans, but this is a stop-gap solution, as I sleep in the bed, and dont like putting gas cans in my sleeping quarters. I averaged between 11.2 and 16.5 miles per gallon, but have a tiny 13 gallon tank that only holds 11 gallons. Are there any larger aftermarket tanks that will bolt into the stock spot, or will a larger tank from a longbed fit? Thanks!

the longbed tanks will not fit. they are about 8 inches longer front to back.

NWMP makes a 13 gallon aux. fuel tank:
- http://www.4crawler.com/4x4/index.shtml#VendorLinks

Also check
JC Whitney, they carry a 22 gallon replacement tank for the early pickups. It will hang down farther and you'll lose some ground clearance if that is an issue.

I wonder if a 16 gallon tank from a mid 80s through mid 90s short bed, single cab truck, would fit.

Seems like you should be getting better mileage though. You might look into tuning up the motor, rebuilding the carb, and making sure your tire size/gearing is as close to stock as possible.

Another alternative is an auxilery gas tank that fits in the spare tire location. Should give you between 10-13 extra gallons. The spare tire will still fit, but will hang slightly lower. Northwest Metal Products makes them. I think 4Crawler has one too. (whoops, looks like he beat me to it <img src="/forums/images/graemlins/smile.gif" alt="" />)

Thanks for the replies! I do need to have some carb work done, when crawling downhill with my foot off the gas, I get some small backfires, and every time I shut off the engine, it backfires a bit. I don't know anything about carbs, but it seems to be running rich. It has the stock 20R engine, stock 4 speed manual tranny, stock 4.37 gears, and 235/75/15 tires on it right now. I have seen the auxillary tanks from Downey that go where the spare sits, but they want too much $ for those. I am planning on making an external spare tire mount, I'll just have to add a gas can mount too.

One problem might be the 4.37 gears. They are factory but only for two years. I suspect that with a 4 speed and 4.37 gears on 28" tires, you're rpms are fairly high on the highway. A little bit taller tire is probably the cheapest way to correct for that and you'd get the benefit of a taller tire. You might try looking for a 30" tire.

I'd fix the carb first though. Then maybe consider a very slightly taller tire.

You can get the tank from NWMP, they make the tanks Downey (and NWOR) sell and you can get it direct for less money.