Radiator and Cooling System

We're using an aluminum crossflow radiator that actually came from Mid Fifty F-100 Parts. They have always had the stock-style replacement radiators, but Sy figured with the popularity of the crossflows in the trucks, she should offer a few versions. I have also done these swaps with a '56-style radiator. Both work great. The key is to always run a fan shroud and the biggest fan that will fit. The reason this one has the crossflow is the cold-air induction/filter box that was made to fit above the radiator. This took care of the sharp turn the intake would need to clear if you ran a filter off to the side as required with a tall stock radiator. The LS's mass air meter fits into the opening and makes for a nice intake solution.

The next problem we run into is the radiator hoses. It's a pretty close fit for the upper hose and the lower needs to make a couple of tricky bends to connect. Rubber ones probably could be found, but the fabricator in me wants to make something a little better looking.

The upper hose is 11⁄2-inch and the lower is 1¾, so I get a few steel U-bends in those sizes and start making up some steel "hoses." To connect them I'll use short pieces of rubber hose and some clamps. You can go a step further and use the polished aluminum sleeve-type ends that come with the stainless flex radiator hose kits that are out there. Summit has just the end covers available. Paint the steel hoses body or engine color and the aluminum ends really dress up the hose. I have even hidden sensors in the bottom of the upper hose by welding on pipe-tapped bungs. The LS block doesn't have any extra water or oil ports for senders.

The LS kind of changes it up and puts the thermostat at the lower hose. The heater hose ports are also right there. The bigger ¾-inch port is for the feed to the heater, the one that goes through the heater control valve. The smaller 5⁄8-inch is the return. The parts store has a neat little plastic 3⁄4x5⁄8 splicer, that and a 2-foot piece of ¾-inch hose got me reconnected to the 5⁄8-inch hose already run for the heater. The A/C hoses were also shortened up to fit and new ends put on. The charge ports have been moved to inline rather than at the pump. The close fit of everything there is going to require a couple of little shields to make sure nothing ever scrapes or burns.

The LS's also have a bleed line that should be connected to the top of the coolant recovery tank or into the radiator at the fill cap. Although it's only ¼ inch in diameter, it bleeds off the air in the top of the engine within the cooling system. The crossflow radiator we used has a ¼-inch pipe port just under the radiator cap, so I plumbed a bleed line to that point.

The electric fan is mounted in a fan shroud I made from an F-100-style radiator fan shroud that Bobco had lying around. A couple of cuts, bends, and a few welds and it fit perfectly. The shroud was already made in Brightside stainless, so a few minutes on the buffing wheel had the new welds looking good.

Mounting the Derale Tornado 16-inch fan is easy, it just slipped into the opening from the radiator side and I drill four 7⁄32-inch mounting holes in the shroud. Some polished 10⁄32 button heads and Nylok nuts and the fan is secure in its shroud.

Control of the fan comes from the computer. It's set to come on at 190 degrees and if the A/C is turned on. The temp is adjustable within the computer.

Fire-up and Tuning

This is always the best part. Turning the key and hearing it run. The usual checks were made first: fuel pressure, battery charge, trans in park, brake on, everybody out of the way. Street and Performance had the computer dialed in and after a warm-up and check of the trans shifting we jumped in and took it around the block. It accelerated smoothly (and quickly compared to the old 460) and the trans shifted at the proper points. We were quite happy with the maiden voyage and the panel truck seemed to be too. The front end felt lighter and the truck just seemed to drive nicer.

To put the final touch on the install, the next call we made was to a local computer tuner who could dial in the computer to what the panel truck's owner wanted while running it on a dyno to simulate highway speeds. This is very common now with the computer-controlled engines. The new Mustangs, Camaros, and Dodges all have tuning programs available that can add 20-30 horsepower and the same in torque when used with a few bolt-ons such as a cold-air intake and long-tube headers.

Ryan Cunningham of Cunningham Motorsports in Murrieta, California, is no stranger to performance tuning. Just 28 and he already has a close following of road racing customers he keeps in the winner's circle. Bobco made an appointment and drove it on over. Ryan and Mike, Ryan's right-hand man, got it placed and tied down on the dyno, then Ryan connected his laptop to check out the computer. He made a pull on the dyno to see what horsepower and torque the engine was making and to use that as the baseline. It ran a 336/352.

Ryan has done so many of these LS engines he has the program memorized. It didn't take long for him to load the new program and dial it in. You could hear the engine getting stronger with the dyno runs. Its final run showed 362 horsepower and 375 lb-ft of torque at the rear wheels. That will get you through traffic very quickly. When Ryan was satisfied with how the engine was running, he and Bob took it out on the street for a testdrive. When they came back, the smile on Bob's face and the thumbs up told me we had a winner. The acceleration compared to the old 460 is night and day. The little small-block revs faster and the trans shifts smoothly when it's supposed to. It is the perfect complement to the Corvette suspension the panel already has.

The owner has had the panel for a couple of months now and drives it almost every day. He has been monitoring his plumbing business with it. To say he loves it is an understatement. If you should see him at a show, he is more than willing to tell you how awesome it is.