Abusing the rollers on Westech's chassis dyno, our bolt-on plan resulted in a 121hp gain a
Having a 440 car comes with a certain distinction. After all, the torquey 440 was one of the largest production engines offered in a factory musclecar, and there's no debating that the factory moved those heavy bruisers with ease. The "440 Magnum" emblems on the hood of our '71 Charger R/T gave ample warning to would-be contenders that there was a lot of engine under the hood. But in today's mean streets, the factory package isn't always enough to keep the more serious street rats at bay. Sure, it's unfair to compare a dead-stock musclecar to the hopped-up street warriors roaming the boulevard, but when the light turns green, there's no one hanging around to check the engine's date codes. Try as you might to keep a low profile, a Green-Go '71 R/T with full stripes and spoilers and those 440 emblems on the louvered hood just begs for a confrontation. Thus, we needed to ensure we were packing a serious punch.
The 440 in our Charger was something of an unknown quantity. The engine had already been rebuilt when the car was acquired, and we had little clue as to what was inside. Externally, the engine was stock, with the correct factory iron intake, carb, and exhaust manifolds. We investigated and found just over 0.450 inch of valve lift, so it would seem the cam was stock or near-stock in specs. The "factory" 440 combo gave us 252 hp at the rear wheels on Westech's chassis dyno, and with an upgrade in the exhaust system to headers and 211/42-inch duals, we had upped that to 280. We knew, however, that really busting out the big numbers would require getting inside and breaking out the serious hardware.
While turning a number in an unrestrained drag car is one thing, this Charger serves time strictly as a street car. We had power brakes, air conditioning, and day-to-day driveability considerations to contend with in choosing our package. We wanted to be able to pack up the car for the weekend, fill it with gas, and head out for a drive up the coast without scaring the kids. With those constraints, huge, lumpy cams and sky-high compression ratios were out, but we figured there was still plenty of room for improvement with conventional mods. Since the engine was fairly fresh, the short-block would remain untouched, but we would hit the key areas of heads, cam, and induction to really make this 440 come to life.
The 440's response with the absence of much cam duration indicates that an exceptional set of heads must be a big part of the buildup program. Back in our shop, collecting dust on the shelf, was a set of fully ported 452 iron heads, which delivered well over 300 cfm of airflow. We had used these several years ago as a pair of port-development heads. After extensive rework and testing, the port flow was outstanding. Having no further plans to use them in engine R and D, we figured why not put them to use on the Charger's 440? Would they be our first recommendation for a buildup today? In a word, no. If we hadn't already had them ready to run, we would have looked toward an aftermarket head.
We wanted big power from our 440, which meant opening it up to get at the heart of the mat
We heaved off the 440 Magnum cast-iron intake and factory AVS carb. These things don't mak