Performance buffs have been taking classic Boss 429 engines and boring them out to 4.375″, which are are .015 larger than the original, and adding some modern technology know-how to pump out over 670-hp from these beastly motors.
The grinding out will offer up 432 ci displacement, but this block can support up to 598 inches! Then they coat the forged aluminum diamond pistons with high-temp magic-sauce, install a new, stronger crankshaft, a modern belt-drive timing system, extra-deep oil pan to keep everything running cool and well-lubed, beehive springs on the valves, a new carb and an aluminum intake manifold.
You don’t always need a new motor to soar above stellar horsepower numbers. But a little modern technology can help.