With all the talk about Mopar small-blocks during the 2010 AMSOIL/Mopar Muscle Engine Challenge, we didn't want our big-block followers to feel left out, so we thought we'd let you follow along on an engine we're building for one of our own Mopars. Those of you who read Mopar Muscle magazine regularly will recognize this car as a '71 Road Runner we picked up from friend Dale Mathews in North Carolina. Since we purchased this car sans the original engine, it's perfect for a swap to a brawnier big-block that will turn heads at cruise night and run impressive elapsed times at the dragstrip. So far we've painted the car, restored the interior, and installed all new suspension, brakes, and rear differential in previous articles. To get the car moving under its own power, we also installed a warmed over 383. While this engine runs fine, it's basically stock and doesn't really satisfy our need for power. This month, we'll tell how we decided which powerplant to build for this car, and show you all the parts and techniques we used to accomplish the job.

Noting that the low-deck B engines that used 440 crankshafts in our 2009 engine challenge made impressive power using a bunch of factory parts, we decided that in the interest of a tight budget we'd follow this theme with this engine as well. Of course it helped our decision that we had a pretty clean 400 block sitting in the shop along with a factory forged 440 crankshaft, not to mention the 400 will bolt right in place of our car's 383, making for an easy swap. Using the parts you have around the shop certainly makes sense whether you're on a budget or not, as it cleans the shop and puts to use items that were just sitting around. We were lucky, since our 400 block and 440 crank form the basis for a powerful and economical Mopar big-block.

Knowing we'd need aftermarket forged pistons and connecting rods for this engine, we called 440 Source to check out our options. 440 Source has plenty of stroker kits available for big-block Mopars, and their prices are hard to beat whether you need an entire balanced rotating assembly or an individual engine part. Since we already had a factory forged crankshaft, we didn't need an entire rotating assembly, opting for a set of their forged H-beam 6.76-inch connecting rods and a set of forged, flat-top pistons which will give us a compression ratio of just over 11:1. Priced right, these pieces from 440 Source are rated to 1,000 horsepower, so they will be plenty tough for our street engine.

With the major pieces of our bottom end in place, we took the parts to Auto Performance Engines to be machined, and ordered our Clevite bearings, Speed Pro piston rings, and Fel-Pro gaskets from Summit Racing Equipment, along with a new Melling high-volume oil pump. For a street engine of this type, internal oiling is adequate so long as you upgrade the system, which we did by machining the block for a larger 1/2-inch diameter Milodon pick-up, and installing a Milodon 7-quart oil pan with a factory windage tray.