Fuel tank is made of...?

[SWEET7T]

I want to run a larger tank on my SWB. I've heard that the LWB 36gal will not fit in its place. So I'm thinking of welding one up (I've made 2 transfer tanks for other trucks).

I would just make a transfer tank to pump in to my factory unit, but I don't want to molest the bed side for a filler since I have a camper shell on the truck half the time.

So my plan for the sending unit assembly is to cut the mount from the existing tank (junkyard), and weld it to the new tank. Of course my depth cannot change, but there is a lot of unused space around the factory tank.

So, is it mild galvanized or what?

[ChevLoRay]

I seem to recall the tank on my '69 having the appearance of galvanized metal. I have not had one of these tanks down, but wouldn't be surprised if it is a polymer/plastic. It may not be, but I wouldn't be surprised.

Why do you want the larger tank? I know you said something about a camper, but what is driving this issue? Have you looked at a LWB chassis/tank configuration to see what is there and how it might be adapted to your chassis?

I'm playing devil's advocate, so don't dis me too much.

[Restrorob]

I replaced my tank last summer and it's steel with a plastic type skid cover on the bottom. If it's galvanized I can't tell from other galvanized metals I've seen/welded, I have welded holes in tanks years ago and don't recall them being galvanized.

But HERE is a option to cutting/welding a sending unit bib in a home built tank, Your stock tank is 13 3/4" deep at the sending unit bib so the 12" unit should work fine.

Sooo, What's your plan for filling this add-on tank ?

Transfer from the stock to it then back as the stocker gets low ?

[SWEET7T]

My first plan is to just replace the stock tank with a larger unit that I would fab up. Using just an ~8" square cut from the top of the factory tank so that I could mount the factory sending unit and keeper ring, and weld the 8" to the new (replacement) tank.
All I can remember from the factory unit is that it is indeed metal with a plastic 'skid plate' like cover along the bottom. I may try to junk yard another tank and take the welder to it and see how well I can make something stick. The reason for the question is to just be able to use the factory sending unit assembly by welding the piece of the factory tank to the new.

Running an aux transfer tank mounted in the bed would be cake, if I didn't have a camper shell on the truck. The issue with the camper shell is that it really limits my way of refilling the aux. Without the camper shell, I could just stick the pump nozzle over the bed side and fill. With the shell I would have to bore a hole in the side of the camper and plumb it, or add a second fuel door on the side of the truck. If I didn't ever use the shell, I would just make a small box (bed rail height, full bed width) to hold another 25-30gal, and with the flip of a cab-mounted switch open a solenoid valve and energize a small pump and just refill the factory tank (which is what we did to my dad's Dodge; 36gal main, 52gal aux, 1000+mi range empty).

The use of the shell is for camping. The wife and I don't mind spending a few nights in the bed of the truck , plus the bonus of your crap not getting wet. If I had a small trailer then I would ditch that shell in a hartbeat and none of this would matter.

I'm getting 17+ with the truck easy when empty, but 350-400 range just kinda sucks after awhile. Truck spends 75% time on interstate for travel/camping/dirt bikes.

[ChevLoRay]

Rob, thanx for the info. I didn't know...hadn't seen one. Just guessed.

[Restrorob]

Hey, No problem CLR.....Just sharing what I found. Unless one gets up under the truck it does appear that they could be plastic.