Mopar 440: The Making of a Mean Big Block Mopar

Even though the 4.15-inch stroke Mopar Performance forged crank was a brand new piece, we had it run through the Magnaflux machine to be sure there were no hidden cracks (there weren't). We also balanced the crank, pistons, and connecting rods, which required taking a little material off of the crank counterweights.

When the block came back from the machine shop, every hole was hit with a thread chaser to make sure the threads were clean and ready to accept fasteners. The last thing you want to do is force and possibly break a bolt or stud because of junk in the bolt hole.

Don installs the Mopar Performance solid lifter cam. The cam features 296 degrees of advertised duration and .557 inches of lift. It's kinda borderline for a street car, but near perfect for bracket racing. The cam will be degreed in once the engine is finished.

While Don has built engines before, the 440 is his first race motor, so he made sure to check and recheck all tolerances and clearances. Here, he's checking cap to crank journal clearance on the front main bearing cap with a dial bore gauge. It speced out to .002 inch, well within factory tolerances.

To verify the clearance measurement he got on the front cap, Don checked the rest of the caps using Plastigage. The procedure is simple: lay down a strip of Plastigage on the journal, torque the cap (with bearing) to 85 foot-pounds, then measure the Plastigage. All clearances hovered right around .002-inch.

The connecting rods, pistons, and piston ring set are from Mopar Performance. The rods are forged from 4340 aircraft quality steel. The flat top pistons deliver 10.5:1 compression and can be used with press-fit or full floating rods.

The rod and piston assemblies are slid into the cylinder bores to check rod-to-crank journal clearance (using the Plastigage method outlined earlier) and piston ring end gap. Rod clearance checked out fine. The top rings had to be file-fit to achieve the proper.018-inch end gap.

Don lays down the Mopar Performance solid windage tray and oil pump pickup. We were originally going to use a Moroso pickup, but we goofed and got one with a 3/8-inch pipe thread (standard big block size) instead of the larger 1/2-inch Hemi style thread that the MP siamesed block has. For our purposes, the Mopar pickup will work just fine.

The Moroso deep sump oil pan holds seven quarts of dinosaur juice versus the stock pan's five quarts. It has a one-way baffle that forces oil toward the pickup area and keeps it there.

These Mopar Performance Stage VI aluminum heads come fully ported, providing 12 percent more flow on the intake side and a whopping 70 percent on the exhaust side over stock big Mopar heads. The Stage VIs also feature raised rectangular intake and raised exhaust ports, and 78cc closed combustion chambers. We assembled the heads with 2.14-inch intake/1.81-inch exhaust valves, dual valve springs, locks, and retainers.

The 1.5-ratio Crane Gold Race roller rockers are sold individually--you have to specify right or left offsets. You have to supply the shafts, shaft spacers, shaft hold downs, bolts, and rocker locating springs. We used Mopar Performance parts to finish the rocker installation.

Rocker arm orientation is critical on a big block Mopar. There are three types: left offset intake, right offset intake, and straight exhaust. The rockers must be assembled on the shaft as shown so the rocker tips line up properly over the valve tips. You'll know if you messed up when you can't run the shaft bolts all the way down and the intake rockers don't line up.

This Mopar Performance M1 aluminum intake is designed specifically for the Stage VI heads. The single plane manifold has large rectangular ports raised to match the intake ports on the heads, and those big runners are raised to help keep the air/fuel charge cooler. The manifold is available for standard Holley squarebore or Dominator carburetors.

This 830 cfm Holley Pro Series HP carburetor has neat features like 1.75-inch bores, jet extensions, milled airhorn, choke tower, and choke control, four-corner idling, and screw-in air bleeds. We added an open phenolic spacer to help give the air and fuel a straighter shot at the intake ports and to isolate the carb from manifold heat.

Don screws down the thermostat on the CSI billet aluminum electric water pump. You can also see the Mopar Performance electronic distributor. It has a race advance curve and mechanical tach drive, and will be hooked to Mopar's "chrome" electronic ignition box. Under that shiny chrome front cover is a Cloyes Hex-a-Just roller timing chain.

Here is the 440 as it stands. There is still more work to do on it-degreeing the cam, adjusting the valvetrain, figuring out headers, etc.-but the basic horsepower-making bits are in place, waiting for fire-up day.