It's one of those things everyone needs for their ride: a gas tank. Sometimes you can get away with a stock tank in a stock location, or even use another make and model's tank in something entirely different (for example, a '66 Mustang gas tank fits nice and flat in the trunk of a '32 coupe).
But not all gas tanks are created equal, especially when you have a truly custom application. So let's say you have a 'glass '41 Willys pickup mounted to an S-10 chassis and you want to fit a 16-gallon tank under the bed. What do you do?
Everybody starts with a drawing...
Everybody starts with a drawing of what they want. This is the illustration we made for a custom fit stainless steel tank to be installed under a truck bed on a '41 Willys pickup.
A quick call to Rock Valley Antique Auto Parts in Stillman Valley, Illinois, solved this problem. In business since 1971, the company began building stainless steel gas tanks in 1981 when they recreated a tank for a '34 Ford (which won the NSRA's Best New Product that year). Since then they've built tens of thousands of gas tanks for nearly any application (boat, plane, car, scooter, military, maintenance, etc.) you can imagine. Now known for their line of custom stainless steel gas tanks, their business also supplies rodders with all sorts of fabricated parts (battery boxes, running boards, bumper brackets, dashboards, etc.) and their inventory exceeds 8,000 parts for Ford and Chevys from 1928 to 1976.
Rock Valley suggests the home builder first make a cardboard mock-up of a tank and fit it to the space you intend to have the real one. That way you can figure out how the rest of the car's parts (exhaust, rearend, crossmembers, etc.) might interact with where you want your tank.
Once Rock Valley knows the...
Once Rock Valley knows the dimensions of each piece of the tank, they can begin to shear the quarter-inch stainless steel used in the construction of the tank.
Then, to get a custom-made tank, you have to supply Rock Valley a drawing of what you want. It should include the height, width, and length of the tank (the formula HxWxLx.004329 will yield the tank's capacity) plus where the filler neck, vent, roll-over valve, fuel pickup, TPI pump location (if needed) and, if you have it, the radius measurement of the corners (Rock Valley will do that for you if you don't know what it should be). You'll also need to tell them what kind of gauges you'll be running, as the mounts for the electrical senders are different between the different gauge manufacturers, and you'll need to indicate the tank's orientation (which way is "front" and "up").
Once they receive your drawing they look at it to see if you missed anything and how feasible the construction is. They'll call or fax you with any questions and, when they're satisfied with what it will look like, they'll send you their drawing of your tank to confirm everything. Once you give the okay, the tank will be made to spec and you'll soon be down the road. The following photos illustrate just how involved the process of building gas tanks is-going from a stack of flat stainless steel to a rather nice custom addition to your ride!
 Rock Valley also designs the...  Rock Valley also designs the tank's internal baffles that help control the gas from sloshing around while driving. |  The top and bottom pieces...  The top and bottom pieces of the tank are also cut on a 10-foot shear. For some of the smaller pieces requiring a radius, a high-speed bandsaw with a stainless steel blade is used. |  This is the die set used to...  This is the die set used to punch the hole for the sending unit. |
 Once the sending unit hole...  Once the sending unit hole is punched, four small mounting holes are punched around its edge. |  After the appropriate amount...  After the appropriate amount of holes are punched, all of the pieces that will make up the new tank, including the internal baffles, await assembly. |  Next the pieces move to the...  Next the pieces move to the press where a special die has been made to create the length-wise radius found in the lower section of the tank. Adding the radius to the bottom section of our tank also creates the front and rear of our tank, too. |