We all know the 440 big-block is the largest displacement V-8 engine built by Chrysler, and when it comes to a combination of torque, power, and drivability, the 440 ranks as one of the best engines ever built. Instead of utilizing a high compression ratio or aggressive cam grind for its muscle, the 440 relies on sheer size, making great power from an idle with enough torque to get even the heaviest Mopar C-Body moving quickly. And while the Mopar 440 does several things very well, we've always felt that with a few tweaks the engine was capable of well over the 375 horsepower rating it got from the factory.

The 440 is definitely a versatile engine, having been installed in Mopar passenger vehicles from muscle cars to station wagons, in trucks, and even in boats. Even the highest performing factory 440, the 390 horsepower Six-Pack (or Six-Barrel) version, had a relatively mild hydraulic flat-tappet camshaft and non-adjustable rocker arms, ensuring years of smooth, maintenance free operation. Even better, 440s are still available in scrap yards, from core suppliers, or even in running vehicles if you know where to look.

The 440 we're featuring in this build was actually in a low-mileage Winnebago motor home that was built on a '74 Dodge truck chassis. We found the engine in the local classified ads, and bought the engine and transmission from the owner for a paltry $400.00. The motor home had seen better days and was being scrapped, so the owner simply had no use for the engine any more. As an added benefit, this engine (like many early to mid-seventies truck and motor home 440s) was equipped with a factory forged crankshaft. So when we needed an engine to build as a dyno mule to test some parts, this 440 fit the bill nicely. Even better, the engine had very little wear so it wouldn't need much in the way of machine work.

Many engines used in motor homes now have high-mileage and are completely worn out, but some motor homes, especially older ones, didn't see much use. The motor home our engine was in only showed some 40,000 miles on the odometer, and was only used once or twice a year for family vacations. When we disassembled this engine we found that all of the internals were standard, and the cylinder bores were still round and straight without any ridge at the top. Since we had a set of older, standard bore Speed Pro forged, flat-top pistons on the shelf we acquired years ago at a swap meet, this engine was the perfect excuse to keep our pistons from collecting any more dust.

The only downside to using our Speed Pro pistons was that the compression of this engine with the stock heads and the pistons .014-inch down in the bore at TDC, would only be around 9.0:1. Since a 440 with compression this low wouldn't make enough power to impress anyone, we took the opportunity to use a set of “915” casting cylinder heads that were also sitting on a shelf in our shop. We had picked these heads up years ago at a swap meet as well, paying only $100 for the pair. After cleaning the heads up we cut the exhaust seats and installed a set of stock exhaust valves from some 906 heads, a set of Comp 928-16 valve springs, and performed a simple port-match job and valve job to make them serviceable. With a closed chamber design and a measured chamber volume of 82cc's, we calculated the static compression of our 440 using the 915 heads to be 10.18:1, so our 440 will run great on pump gas.

For the rotating assembly of this engine, we simply polished the crankshaft, installed ARP rod bolts and main studs, and new stock replacement engine bearings from Summit Racing Equipment. We fitted our Speed Pro pistons with stock rings, and sealed the engine with a fresh set of gaskets and seals, also from Summit. As you likely can tell, we're building this 440 on a budget, and simply replacing the parts necessary to make it perform properly and last, but not going over the top with any lightweight or exotic pieces. Using a new Melling oil pump with a factory B-Body HP oil pan and windage tray also keeps things inexpensive, but works just fine for an engine like our mild big-block.