Prepping A 440 CID Mopar For Street Duty

Chrysler’s 440cid big block was the dominant engine throughout Mopar history. Not the HEMI, as many historian’s will offer, but the 440 which single handedly dominated during the ‘60’s, overcoming many a challenge from 428cid Ford Mustangs and 396-powered Camaros. For certain the 440 had those guys covered in most straight line contests especially when it was housed in one of those wonderful torsion-bar supported Mopar frames. While the 426cid HEMI may have been the legendary engine of the time and the basis for Top Fuel engine development, it was the 440 that set the trend street and bracket competitions.

While the 440 ceased to be in 1974, the mold was cast and the wrecking yards were chock full of these race-ready engines. By the late ‘70’s a rebirth of Mopar interest occurred chiefly centered on the exploits of an orange Charger that seemed more airplane than land-based car. Today 440’s are still a powerful force for the Mopar engine builder looking for great drivability and reasonably priced parts. Crate engine HEMIs may be the rage, but building a 440 for street use is a great way to make big reliable torque numbers without really trying.

Building the engine

For the build up engine builder Rich Sephton used a 1969 vintage 440cid block complete with original heads and  crankshaft. The block was not an “HP” block, but the extra thickness found in the webbing and cylinder bores was not required for this engine application.

The original block was hot tanked to clean the many layers of paint and grime, aligned bored and decked to achieve a straight, square block and outfitted with new brass freeze plugs. The block was bored 0.030-inch and final honed with a 440-grit hone using a deck plate to ensure accuracy. The engine’s valve train valley was painted with electric engine armature paint and the exterior of the block was painted black to absorb heat from the inside of the engine.

The original steel crankshaft was turned 0.010-inch on the main and rod journals (featuring micro-polished surfaces and oil holes that had been lightly opened and then chamfered smooth) and then set in place on the Federal-Mogul bearings that had been deburred and cleaned before installation.

M & R Engine Building in Glendale balanced the internal components before they were torqued in place with ARP bolts. PAW “Super Stock” connecting rods (featuring smoothed beams and high strength ARP bolts) were attached to Speed Pro Teflon-skirted pistons and single moly Sealed Power piston rings.

End gaps for the first and second rings were set at 0.012-inch and wall to piston clearance at time of assembly was 0.002-inch. The oil ring was a three-piece unit.

The 440cid engine has traditionally suffered from low-tech camshaft technology. The COMP Cams Xtreme Energy camshaft delivers quick revving street performance. A 268-degree hydraulic flat-tappet camshaft according to the current specs, the cam profiles were slightly under the half inch point for lift on both the intake and exhaust side.

Lobe separation angle came in at 110-degrees. According to Sephton, while the camshaft works great, it lets others know the engine is modified but not to the point where it is incompatible with power equipment. At idle, the engine pulls 15 inches of vacuum, perfect for power brakes, etc.

According to Sephton, high quality pushrods are critical to Mopar engine life. For this reason he uses the top of the line Mopar 3/8-inch units. COMP Cams valve springs, retainers and locks were used along with a double roller timing chain and sprocket.

The valve springs were set to 1.900-inch installed height providing 125 pounds of seat pressure when closed. Original style but new Mopar shaft rockers and hard chrome shafts were used along with new Grade 8 bolts to keep them in place.

On the bottom end, the oiling system uses a Milodon oil pickup and Milling oil pump set for 50psi oil pressure at 2500rpm. Sephton notes that 440cid engines do not like high oil pressure. To that end, the Federal Mogul main bearings use a 3/4 surround oil groove. This oil groove does not have 360-degree grooving forcing the oil back out of the bearing through the last 90-degrees of the crankshaft revolution. A stock windage tray and 5-quarter stock oil pan are used, although Sephton readily admits that a larger pan might be nice for this level of engine.

Topping it off

The original 440cid cylinder heads used here were of an open chamber design. Combined with the flat top Speed Pro pistons, final compression was 10.5:1 making them compatible with pump gas. The original heads were also hot tanked and given a three-angle valve job, hand lapped in place before the springs were installed. Sephton port-matched the heads to the Edelbrock classic Performer intake, a throwback to the original Dukes intake used on the show. Reproduction exhaust Manifolds from Year One were purchased, the heat risers removed and the resulting hole filled with a pipe plug should it need to be replaced at a later time.

The Holley 3310 750cfm carburetor was slight reworked and outfitted with #72 front jets and a 3.5 power valve backed up with a stock jet plate set of secondary system. A phenolic one-inch carburetor spacer was bolted between the carb and intake to help fuel mixture and heat isolation. An original style “orange box” Chrysler electronic ignition fired the Champion R12Y spark plugs, which were gapped to 0.040-inch. The distributor was re-curved to 10-degrees advance at idle and full advance of 38-degrees at 2800rpm.