 14a. It's time to tackle the...  14a. It's time to tackle the air delivery system. Our goal here was to hide the entire system under the bed, so that once we installed the bed floor we'd have a clean area to haul stuff in. A standard 5-gallon round air tank wouldn't fit anywhere around our chassis, so we built our own air tanks from 24x8x4-inch by 0.180-inch wall rectangular tube steel. |  14b. We bought the tubing...  14b. We bought the tubing from a local steel yard's scrap pile for 90 bucks and TIG-welded 1/4-inch-thick end plates to make the tubing into air-tight tanks. We then welded bungs into the tanks to plumb a Master Image Customs auto-reset 145-psi pressure switch, air transfer lines, and a sending unit for a Dakota Digital air pressure gauge (14b). The threaded bungs at the top of the tanks will fit into the bottom of the cross braces of the bed, so that we can bolt the tanks directly to the bed braces. |  15a. AccuAir's valve block...  15a. AccuAir's valve block is very compact, well-engineered, and slick-looking. |
 15b. It will reduce the amount...  15b. It will reduce the amount of space needed to plumb the air system. There are inlet and outlet ports on each end of the manifold, and the 'bag ports are numbered for easy identification when wiring and plumbing the system. We built a 16-gauge sheetmetal mounting bracket to attach the valve block to one of our reserve air tanks (15b) and brackets to mount each of our Air Zenith compressors to the framerails, just behind the cab of the truck. |  16. Here's a look at how compact...  16. Here's a look at how compact the system is when it's in place. The only other components other than what you see here are an identical air tank and compressor mounted on the other side of the chassis. We plumbed our air system using DOT-approved plastic air line and stainless steel fittings that we bought from GO-EZ Customs in Placentia, California. Thankfully, GO-EZ is open on Saturdays, so we were able to buy everything we needed from those guys when the rest of the custom world had taken a day off. The air tanks are connected together via a single 1/2-inch hose to create one large tank, and the airbags are plumbed with 3/8-inch hose. The air compressors are wired to a pair of relays that are connected to a single pressure switch plumbed into the air tanks. When the air pressure within the tank drops below 145 psi, the pressure switch triggers the relays to turn on the air compressors until the air tank reaches 200 psi. |  17a. Although the AccuAir...  17a. Although the AccuAir valve block does come with a sweet insulated connector to aid in wiring, we still had to provide your own switch cable and switches. We bought nine 25-foot spools of primary wire and four Carling single-pole, double-throw, momentary switches from our favorite electronics store, Orvac Electronics in Fullerton, California. |
 17b. We then made our own...  17b. We then made our own switch cable and installed the switches into the bottom of the dash of our truck. The switches send a positive 12 volts to the valves to activate them, and the valves are grounded to the chassis of the truck via a ground strap built into the plug at the manifold. |  18. The heart of the entire...  18. The heart of the entire system is an Optima RedTop battery, which is grounded to the chassis via a large, 2-gauge cable. Another 2-gauge power cable is routed from the positive battery post to a distribution block on the chassis to power the compressors, relays, pressure switch, and dashboard-mounted switches. |  |
The Final Word
So, that's how the suspension of our '67 was made. It was all done in a massive effort to lay this truck flat on the ground and keep the floor of the cab looking like this. Look at all that legroom! Stay tuned for the next installment of this series, because we'll be showing you how we stuffed an all-aluminum Chevy LS2 into this truck and made it run with a carburetor and electronic Overdrive transmission.