Mounting a Gas tank

As a part of my LS1 swap project I am replacing my stock Studebaker gas tank with a new, deeper tank from Tanks, Inc. The new tank will have an internal fuel pump to provide the needed pressure for the LS1 EFI.

Here's the question. The Studebaker tank was mounted directly to the frame. The new tank, actually a repro tank for a 53-54 Chevy, does not have the mounting tabs and is designed to be mounted using steel straps. My original thought was to mount the straps to the trunk floor, backing the bolts with large fender washers or backing plates. I have re-thought that and what I want to do now is run a couple of cross pieces between the frame rails in front of and behind the tank and then attach the straps to those. The straps would then hold the tank against the underside of the trunk floor. My questions is what type of material to use? The distance between the frame rails is about 38 inches. The frame is a box design with a 1 inch lip on the bottom that I can place the cross piece on top of then drill through to hold the cross piece in place. The tank is a 16 gallon unit so full of fuel it will weigh 125-130 pounds. The straps are 1" wide stainless steel and would be spaced evenly on the tank. My thoughts were to use angle iron or U channel. I believe I could also find some stamped channel of some kind too. What would you folks suggest? What thickness of material? The things I am thinking of is something that will be able to carry the weight without flexing or bending, but not be too heavy. I also want to position the straps in a way that the tank won't shift from g-forces of braking, turning or accelerating. One final thing, I want to put some sort of insulating material between the top of the tank and the trunk floor. I was thinking of some sort of dense foam, but not sure what material. Any suggestions? If I glue it to either the tank or the floor then the other side have a slightly tacky texture that would also help in keeping the tank in position so it would not slide around.

thanks for any ideas

Pat

I think I would probably fab up a couple crossmembers from 1 x 1 1/2 rectangular tubing to hang the straps off of.... Plenty strong and not a lot of extra weight. Easy to make it look good, too. I would think you would want to be very selective about a sound deadener material, you certainly would not want anything between the tank and floor that could trap moisture and start a rust situation........ Nothing comes to mind right off for an insulator..... Maybe some of the bed liner stuff??????

To add to Dave's, tubing is more rigid in span than solid, and there're lots of configurations of "flat" tubing. Are you planning to atatch your new "crossmembers" to the frame or floor. If the existing floor is your choice, and in good condition, then plug welding the new cross pieces will spread the load, and you can get away with a smaller cross section tubing/channel. If attaching to the frame, then you need more rigidity.

Since you're talking about a pad sounds like you're attaching to the floor. The typical factory pad from that era was similar to tar paper, about 1/4" thick, often with a waffle pattern. Here's something similar offered by CPP; http://www.classicperform.com/Store/...s/4972GTMP.htm
Although, if noise insulation is the main objective (and a good one) a piece of aluminum foil/bubble wrap type insulation would do the job, cost next to nothing, is available at your local home supply store and won't hold moistrure.

if the tank is out a 55 why not buy the floor pan repops for the 55 and the straps and see if it will work drill5/16 holes and plug weld the 55 stuff in your trunk ?they used tar paper in strips or rubber can be had from a old truck tube .

Thanks guys for the quick suggestions.

Let me clarify. My plan is to attach the crossmembers to the frame, then bolt the stainless straps to crossmembers to hold the tank up against the trunk floor. If there is folly in this idea, please let me know. I thought about the fact that the body, including the trunk floor, is bolted to the frame so there could be some very minor movement between them. That is one of the reasons I want to put some sort of insullation between the tank and the trunk floor, the other reason being some sound deadener because of noise from the electric pump. The trunk floor is in excellent shape, and is also fully upholstered inside, so I really have no reason to replace it. That would be a great idea if I was working on the body.

What wall thickness would you suggest on the rectangular tubing?

thanks again

Pat

1/8 wall steel tubing i have used 1by1 tubing will do the job or you can use bigger may look better if you are hooking in to the frame. no you would just weld the tank braces from the 55 to your good truck floor not the hole trunk pan

I was just brainstorming with a friend of mine and I think we have come up with a great solution. Instead of putting the tank up against the trunk floor, I will mount the crossmembers to the top of the frame rail and connect the two crossmembers above the tank with two pieces of 3/16 x 1.5 stock so the straps snug the tank up against those instead of the trunk floor. That way the whole thing is connected to the frame and it takes the frame to body movement out of the equation.

Thanks again for your help

Pat