We'd all love to install a high-horsepower engine in our Mopar, and many of us do modify our engines with aftermarket parts in the quest for more power. In fact, there's never been a better time to be a Mopar lover, as the market is flush with the reproduction parts needed to make your car even better than it was when the first owner picked it up from the dealership. One area of our hobby that technology has really helped advance is our car's engines. Nearly all the parts, including engine blocks and aftermarket cylinder heads, are available for most Mopar applications, allowing us to build engines of larger displacement, and far more power than our cars came with from the factory. But because our older Mopars were only designed to handle a maximum of 425 horsepower, there are some upgrades that must be performed to the car before installing that big engine.

A few issues ago, we built a low deck, 451 stroker for our '71 Road Runner, attempting to make as much power as possible on pump gas, while sticking to a "reasonable" budget. While we did spend money where it counts on this build, specifically the 440-1 aluminum heads from Indy Cylinder Head and roller cam and lifters from Comp Cams, we also conserved money by purchasing our cylinder heads in kit form, using a factory block and crankshaft, and choosing reasonably-priced forged pistons and rods from 440 Source. We also had the machine work done locally at Auto Performance Engines, and we assembled this engine ourselves instead of paying someone else to do it.

Clearly this is not the least expensive engine we could build, as a stock 318 would have satisfied that requirement, but our purpose was to show you how to make big power on pump gas with a normally aspirated big-block. We certainly could have added to our expenses by building a larger displacement engine with expensive billet internals and block, using race specific rocker arms, a belt drive for the cam, and expensive dry sump or external pickup oil system. We stayed away from these parts as the benefits they provide exceed what is necessary to make plenty of power for the average street car. In fact, this engine will require that our Road Runner be modified not only so the fuel, ignition, and cooling systems can adequately support the more powerful engine, but in the interest of safety as well.

This 451-inch big-block is far more powerful than the 383 our car came with, and will have more torque and horsepower than our 40-year-old car was designed to handle. For this reason, we felt it necessary to perform some modifications to our B-Body both before and while we were installing the new engine. In earlier issues of Mopar Muscle, we rebuilt our car's suspension with components from Performance Suspension Technology (PST) and installed front disc brakes from the same company. While we were at it, we also installed a larger diameter front sway bar and a rear sway bar from PST as well. Our 8-3/4-inch differential was also modified with a new 3.55 Sure Grip centersection from Randy's Ring and Pinion. This month, we'll show you what else we deemed necessary not just to make our car able to safely hold the new engine's power, but also to ensure the engine performs up to its potential.