In the last issue of Jp Magazine we covered the installation of our trusty Premier Power Welder into our '68 M-715, aka The Evil Truck. The big pickup is about the third Jeep we've installed this same welder into, so that says something of our affinity for the unit. With the ability to weld, run 110-volt power tools, and rapidly recharge our Optima Blue Top in the field, we thought it was time to turn our attention to other areas of our truck build that had been lacking.
Unlike most of our Jeeps, The Evil Truck's primary role is not that of an off-road warrior. Sure, it has been to Moab, Ocotillo, Glamis, and other premier dirt destinations, but during California's hot summer months it's much more likely to be found at a cruise night, making an ice cream run, or just bopping around town for the hell of it.
However, while the fixed blade Flex-a-lite mechanical fan we've been running does an admirable job cooling the beast considering its distance from the radiator and the fact that there's no fan shroud, we have noticed it seems to run a bit hot during the slow cruise night actions. That is, we think it runs hot. With no functioning gauges in the vehicle, it's sort of hard to tell how hot the engine is, what rpm you're turning, and how fast you're going. And since our primary method of checking the fuel level was to wait until the engine died and then empty the 5-gallon gas can we keep on the side of the truck into the tank, a working fuel gauge would be nice as well. That's why we put in a call to Flex-a-lite and Auto Meter.
The radiator in The Evil Truck is a late-model CJ unit for use with a small-block Chevy V-8 conversion, and it nearly bolted in. Since the radiator fit with very minor alterations, we theorized that Flex-a-lite's bolt-on dual electric fan kit for a late-model CJ (PN 575) would be the perfect choice. And wouldn't you know it, we were right. For gauges, we've been eyeballing Auto Meter's new Z-series line of electric gauges. With subtle black bezels and red LED illumination that mimics the vibe of the military lighting, they look right at home in the dash of our former army truck.
 Flex-a-lite's electric fan,...  Flex-a-lite's electric fan, PN 575 is a bolt-in replacement for '73-'86 CJs. But as we discovered, it's a really nice fit in an FSJ as well. The dual 12-inch fan setup includes mounting hardware, the fan controller, and even the wiring and connectors. In short, it's got everything you need to bolt it in your Jeep. The fans suck 2,500 cfm of air and draw only 19.5 amps at peak power. |  The 18-inch fixed-blade Flex-a-lite...  The 18-inch fixed-blade Flex-a-lite mechanical fan we had been running throws a tremendous volume of air, but at the cost of a lot of horsepower and fuel mileage. However, more than anything, our move to electric fans was dictated by the huge distance between our mechanical fan and the radiator and the lack of a fan shroud. |  After unbolting the mechanical...  After unbolting the mechanical fan, we nabbed some shorter 5/16-inch fine-thread bolts and bolted the water pump pulley back on using some red Loctite. As an added bonus to the increased power and mileage from losing the huge spinning fan, we'll be able to use a shorter lower radiator hose without the big kink in it since we no longer need the blade clearance. |
 The Flex-a-lite fan comes...  The Flex-a-lite fan comes with very detailed instructions. We began by installing the CJ brackets. In hindsight, we should have modified the brackets first before bolting them to the fan. |  A few seconds with a drill...  A few seconds with a drill press and a die grinder and we had the CJ mounting brackets modified for use with our M-715's factory radiator support. Another method would have been to simply drill the CJ holes in the M-truck's radiator support, but we like to do things the hard way. |  With the electric fans bolted...  With the electric fans bolted to the radiator, we mounted the fan control within close proximity to the radiator inlet. Then we ran the wires as per Flex-a-lite's instructions. You can hook up the fan straight to the battery so it stays running even after the ignition is turned off, but we prefer to use a source of keyed-on power so the whole thing goes dead when we throw the kill switch. You can also hook up a toggle switch to turn off the fan for deep water crossings, although in dry southern California that seems superfluous. |
 The capillary from the control...  The capillary from the control box must be run through the radiator at or near the radiator inlet. The fan control has a rheostat to adjust the temperature at which the electric fans come on. We run a stock 195 degree thermostat in this beast, so we set the fans to come on right at 195 degrees. |  The finished fan installation...  The finished fan installation really makes a difference in the truck's slow speed cooling ability. And as an added bonus, we do notice better throttle response and a bit more power with the omission of the engine-driven fan. |  Aesthetically, the factory...  Aesthetically, the factory military gauges of the M-715 are perfect. Mechanically, their 24-volt innards just didn't work with the truck's 12-volt conversion. And the mechanical speedometer cable recently snapped, so we took that as a omen pointing to full gauge replacement. |
 Auto Meter makes a seriously...  Auto Meter makes a seriously fine product. The company's new Z-series full- and half-sweep electric gauges in 2 1/16-inch size would drop right into the factory mounting holes. We used the company's 3 3/8-inch speedometer and Mini Monster tachometer to round out our package. Since the electronic speedometer required it, we also ordered an Auto Meter hall-effect sending unit and one of the company's 12-volt adjustable fuel level senders. |  No matter what type of vehicle...  No matter what type of vehicle you're working on, if you're doing a complete gauge replacement taking the time to label the wires will save you some headaches even if you're not planning on using all of the factory wires. In our case, we hooked up to the factory lighting, power, and fuel sender wires, but left the rest alone. |  With the factory wiring harness...  With the factory wiring harness disconnected, we yanked the factory gauges and installed the Z-series Auto Meter units using the supplied mounting hardware. |
 The hall-effect sending unit...  The hall-effect sending unit for the speedometer bolted right to our Advance Adapters Atlas transfer case. The hall-effect sending unit is nice in that it only employs three wires: a power, a ground, and a signal wire to the speedometer. |  The Auto Meter adjustable...  The Auto Meter adjustable 12-volt fuel sender fits standard 5-bolt tanks and can be used with any tank from 5 inches to 24 inches deep. The included instructions walk you through adjusting the sending unit's height and arm length based on your tank's depth. |  We mounted our Mini Monster...  We mounted our Mini Monster tach right to the steering column using the turn signal's mounting hose clamp. We hooked up the included shift light, although you can omit it if you like. The tach is adjustable from two-, four-, six-, and eight-cylinder engines and allows the shift light to come on at any rpm on the scale. |
 The finished gauge installation...  The finished gauge installation looks at home, thanks to the matte black finish. We gotta say, it's a pleasure knowing what's going on with our engine and knowing how much fuel is in the tank. And Johnny Law can't gank us for speeding thanks to the fully adjustable speedometer. To calibrate the speedometer, you hold the calibration button and start the vehicle, then drive exactly two miles (use a measured distance or a GPS), then push and release the button again. The speedo is super-accurate. |  Here's our favorite part:...  Here's our favorite part: the night-time look. We hooked the red LED night lights into the factory gauge lighting wires so we still have the ability of running low, high, or no gauge lighting whether or not the headlights are on. And believe it or not, the red illumination really does help retain your night vision. | |