How many times have you asked yourself, I wonder if I can squeeze a few more horsepower from my enduring, yet horsepower-challenged engine? To tell you the truth, there are lots of ways, but the most misunderstood and often overlooked way to improve horsepower is through your trucks ignition system. A high-output, capacitive discharge ignition system can unlock power by reducing spark misfire and increasing spark duration, which basically means a higher probability that all the fuel in the combustion chamber will get burned.
It seems like everyone has an ignition system on the market, but how do you know which one to choose? To help you sort through all the various features and hype, we took it upon ourselves to measure the horsepower gains of the various emissions-legal systems out there with a chassis dynamometer. With these goals in mind, we called on the ignition experts from Crane, Holley, Mallory, and MSD to provide us with their ignition boxes best suited for off-road use.
In all fairness, we needed an unbiased test facilitator with a chassis dyno to actually document our fire findings. K&N Engineering, a leader in the automotive air filtration market, stepped in with test equipment and expertise. The shootout came together with a couple rolls of electrical tape, numerous butt connectors, the boxes wiring diagrams, and our 73 GMC Jimmy. Our Jimmy has a Quadrajet-fueled 53,000-mile 350 with an ancient Edelbrock Torquer intake and an ACCEL 71000 electronic distributor.
We began testing by making a baseline pull (ACCEL distributor and old wires and plugs) on the dyno and took the average from six runs. Each ignition system was then given a turn to burn. We installed each box and new wires and plugs and adjusted to GMCs suggested timing of 12 degrees BTDC. Each box ran six pulls, measuring horsepower from 20 to 95 mph or at 2,400 to 4,700 rpm in Second gear. Each of the six pulls was then averaged into a representative run to produce the results you see below. While most of our squeezing happened with a pair of crimpers, the test results are clear.