How many times have we found ourselves in a self-inflicted trance, drooling over a custom truck's massive mountain motor with its huge BDS 8-71 blower mounted at the summit, then continue to wonder how this mass of ground-shakin' horsepower was wedged between the framerails and stuffed under the hood? We all know cubic inches are what make horsepower, but it doesn't come cheap. It's easy to spend $25,000 or more sculpting a potent powerplant. Our goal is not to build an out-of-the-ballpark engine but an affordable and reliable engine that has some grunt and will not bust the bank. A mild performance engine can produce the adequate horsepower needed to fulfill a custom truck's needs. You don't need exotic, expensive components to achieve this goal.
To improve the engine's horsepower and performance there are a few areas that need to be attended to, such as fuel distribution, air/fuel mixture, combustion, and exhaust. The main components to increase both horsepower and performance are the carburetor, the intake manifold, the cylinder head configuration, the camshaft, and the exhaust system.
An example of building a performance engine would be compared to improving the performance of an average human body. By improving the human body's cardiovascular system, we are increasing the ease of breathing -- inhaling and exhaling -- which will, in turn, allow the heart to pump more oxygen and blood into the body and its extremities. Creating a better flow rate of blood and oxygen to the muscles will improve the human body's performance.
The same holds true for improving the performance of an engine. An engine is nothing more than an air pump. The more air that can be rushed through it, the more horsepower it will produce. We are trying to increase the engine's breathing by increasing the intake and exhaust flow rate. Improving the engine's capabilities to breath and produce a greater flow rate of air/fuel mixture will increase the engine's overall performance.
To improve this engine's intake, we will be installing an Edelbrock AFB four-barrel carburetor and an Edelbrock Performer RPM dual-plenum intake manifold. This aluminum intake manifold will give us maximum power and a broad torque curve. Both power and quick throttle response is common for a dual-plane manifold. To eliminate weight but increase the air/fuel mixture and flow rate, a pair of Edelbrock A356 aluminum cylinder heads has been heat-treated to T-6 spec for maximum strength.
The intake and exhaust ports have been CNC port-matched, which will give us optimum and maximum power. These Bow Tie heads have a 9/16-inch-thick deck surface for maximum strength and positive head gasket retention. The 1.46-inch valve springs will handle valve lifts as much as 0.575 inch on the completed heads. These Performer RPM aluminum cylinder heads have 64cc combustion chambers for improving the performance and retaining the stock compression ratio. The intake and exhaust ports are in the same location for compatibility with a standard intake manifold and headers. The Edelbrock camshaft is designed for street high performance, and it provides power from 1,500 to 6,500 rpm. These hydraulic lifter camshafts are dyno-matched to Performer RPM manifolds for high-rpm horsepower, while maintaining acceptable low-end torque.
We will be following along as the team at M&R Engines performs the necessary machining and balancing of the block, the crankshaft, and the connecting rods to ensure high-quality horsepower and performance. Then we will follow along as the engine is assembled, using parts from the some of the leading aftermarket manufacturers.
After the assembly, the engine will be bolted up to the SIMTEST machine, where the valves will be adjusted and compression checked, then it will be tested for oil leaks. The SIMTEST machine is designed to rotate the engine like a live engine dyno would do, but without firing the engine. It's what you might call a quiet dyno.
As we arrived at Edelbrock, home of the Fun Team, we were greeted by the Engine R&D crew, Curt Hooker, "Dyno Dan" Dragoo, and Robert Jung. Dragoo would be getting seat time behind the controls of the Superflow SF-900 dyno since he would be administering the dyno test. After a couple of strokes with the throttle stick, he pressed the ignition button; the engine instantly lit off. Bringing the idle up to a steady 2,000 rpm, Dragoo then checked the engine's timing, which he set at 36 degrees.
The break-in period was continued for 90 minutes at 2,000 rpm. This ensured ample camshaft break-in and ring seating time. During the uneventful break-in period, the engine's vital signs were given a thumbs-up. Dyno Dan was ready to drop the hammer and pull the hood handle; a couple a raps on throttle echoed a crisp, instant throttle response. As the engine's rpm accelerated to 3,000 rpm, the load was dropped and the loud stick was slammed wide open until it peaked at 6,500 rpm. After four steady pulls, it was then time for a couple of step pulls, which are automatically administered by the dyno itself in 500-rpm increments.
After pulling on the dyno, the computer started printing out results. From the first pull, the engine progressed every pull with the best results of 422.5 lb-ft of torque at 4,500 rpm and 410.2 CB horsepower at 6,000 rpm.
The results brought smiles of approval from everyone.