67-72 C10 LS Swap Fuel System: Under Bed Gas Tank Relocation

We were facing a couple hurdles on our '68 C10 project. We wanted to come up with some kind of 67-72 C10 rear fuel tank, but we also had to feed the injected LS engine. We also didn't want to spend our entire budget on fancy billet fuel system components. We sourced one of our 67-72 C10 under bed fuel tanks, in tank pump, and filter/regulator combo to get the job done, and the above video details the install of our LS swap C10 fuel system.

Lots of things have changed in the world since 1967. Here in 2023, it seems a bit sketchy to be driving 80 down the freeway with 12 gallons of gas riding shotgun behind the seat. Wouldn't it be great if we could move that tank somewhere else to free up some legroom and storage room? Speedway Motors offers 67-72 C10 under bed fuel tanks that we make in our own shop. These will move the tank out of the cab and under the bed where it's out of the way (even if the DOT says in-cab tanks are OK, if originally equipped). Not to mention, these also add much needed rear weight bias in case you're trying to hook up some power, making it a perfect starting point for our C10 LS swap fuel system.

There are a few ways to ready your tank for EFI. It is possible to pull off a 67-72 C10 EFI with stock tank behind the seat and utilize an external, high pressure pump and regulator. This will require some fabrication and modification to a tank that is already over 50 years old and never intended to feed a modern engine. With all this in mind, we chose a Speedway Motors 1963-72 Chevy C10 Truck EFI Under Bed Fuel Tank for our C10 LS swap fuel tank. If you prefer an external pump, there's also a '63-'72 under bed tank without the ring for the in-tank pump. In either case, we decided that these were well worth the money because they solved multiple problems for us.

We like using an in-tank pump whenever possible for several reasons. For one thing, simple feed and return bulkhead fittings on the tank make for clean and simple plumbing options. Also, the fuel in the tank helps cool the hard working pump. There's a reason the OE's have been doing this for decades. Shop around a little and you'll see that it's easy to spend some serious money on a setup like this. That's why we chose the Speedway Submersible EFI Retrofit Fuel Pump Module for our C10 LS swap fuel pump. The Walbro GSS340 pump flows 255 LPH, plenty for our little 5.3, and we make the housing here in our machine shop, making it universal and budget-friendly. Note that since it's universal, there's some fitting required. We go into detail in the above video.

There are a few ways to approach this with a 67-72 C10 gas tank conversion as we have done. As you'll see in the video, we used Earl's Vapor Guard hose and fittings from the pump to the filter/regulator. This stuff is great because it's easy to work with, resistant to modern fuels, and holds the higher pressure needed for modern fuel injection. We routed ours out of the way through the crossmembers tucked up in the frame rail. When we complete the install, we will be adding some protection to ensure there are no points where the hose could rub through and start leaking. To state the painfully obvious, you absolutely do not want gas spraying out under the truck onto hot exhaust and brakes. Take extra time and care to inspect everything here. For the longer run to the front of the truck, we will likely use hardline for extra peace of mind.