Ball Stud Hemi (Arruzza Style) – Mopar Action Article Extra

While performance was primary, the engine had to be handled and built like no other, because replacement parts simply weren’t available. Everything had to be thought out and executed to the highest standard. Gaskets were a major problem–there were none. Head gaskets, intake gaskets and exhaust gaskets all had to be custom made.

The original crankshaft was basically a stock 440 steel 3.75”-stroke unit. Goodbye! Russ Flagel, the owner of Indy Cylinder Head, pulled strings that only he could pull, to have Callies make a one-off custom forged steel unit with a 4” inch stroke and 2.2” Chevrolet rod pin size and a Hemi 8-bolt flange. Why only a ¼” added stroke? Arruzza did not want to have to notch anything. Realize this block is arguably the only one surviving; a mistake would be a major problem. A .030” overbore was required because one cylinder had rust. The .030 over index bore job fixed that. Result: 481 cubic inches.

Compression was kept at a streetable 9.6 to one for pump gas. Ross made custom Boss 429 pistons for the A279. Yes, Ford Boss 429 pistons are remarkably the same, nearly like A279 pistons. The rods are Manley 6.60” length steel “H” beam units rated at over 850 horsepower. .990” pins were employed, taperwall design. Double spiral locks.

The intake was totally reworked for plenum volume and a Holley double pumper. The thermoquad? No thanks. An 800+ cfm blueprinted Holley from AED of Richmond, VA, turned out to be very crisp and the right choice. The plenum under the carb is huge and the runners radiused nicely. Arruzza ported the intake extensively. The intake ports are mildly worked, bowl blended, etc., and much work went into the exhaust ports. He ported the exhaust manifolds and had a custom cam from Cam Motion ground with extra duration on the exhaust side. The intake ports flow better than a 426 Hemi, but the exhaust ports were slightly lacking in flow. That’s why Arruzza worked much harder on the exhaust side. He had Manley make a custom stainless valves 2.250” and 1.940” size, the same as a Street Hemi. He used titanium retainers to help guard against valve float. Because the rocker arms are non-adjustable, Arruzza went with a hydraulic cam rather than using adjustable pushrods, so he could run a solid stick.

Arruzza installed a Moroso 8-quart chrome pan. The timing cover is an Indy Maxx piece that he machined to fit under the stock water pump housing. The pistons and rods he selected are so light, that Arruzza turned down the crank in a lathe, taking out over 3 pounds. He also knife-edged the counterweights.

The vision Arruzza had from the very beginning was not to merely rebuild this engine but heat it up for more performance. The original owner’s son, Scott Ader, custom-built the entire exhaust system for the car with cutouts that came on Max Wedges and Race Hemis.

The rocker gear, very unique to a Mopar big block is similar to some Ford or Chevrolet engines yet also very different. The stud has the ball attached, so it’s not possible to raise or lower the rocker arm. The only way to change the length is to add to, or machine down the stud pads. The set of rockers, the studs and guideplates are most likely the only set on the planet, therefore, much care went into making sure these parts had the best possible prep work so nothing would get worn or hurt when run. All those parts were micropolished and then coated with Casidiam. Come to find out from Extreme Microfinishing’s Ed Miller, that they very much needed these procedures, as the steel they were made from is extremely hard, and the time these parts spent on the dyno was wearing them very quickly. Casidiam is a space-age procedure that is a miracle film that can’t come off or wear off, and eliminates metal-to-metal wear. It’s very popular among Pro Stock and NASCAR teams for that extra measure of protection and slickness and free horsepower gains.

Arruzza also had all the valve stems coated with Calico Coatings CT-10 for preventing sticking valves or wearing the valve guides. Calico also coated all the main bearings. Arruzza used head studs instead of bolts for the best clamping force. He used main studs for the same reason.

Arruzza used an Indy Maxx rear main seal housing. He used a BHJ fixture to blueeprint the deck dimensions, and also the bellhousing dowel pins. The block was index-bored with a BHJ fixture also.

The dyno work on the A279 project was done in 1968 and 1969, and the parts of this engine are all dated 1968 and 1969. The engine is actually the correct date codes for this particular ‘Cuda. The A279 now has 11/32” intakes and 3/8” exhaust valves. Pushrods are custom from Smith Brothers Arruzza hand-blueprinted |the high volume oil pump, polishing the internal passages extensively and drilling the main passages in the block for assurance of oil delivery.

Arruzza sonic tested cylinder wall thickness and found at .030” overbore, the block is thicker than a vintage 426 Hemi. Nice thick cylinders with no core shift. The block is similar to a low deck 400, except using 440 Hemi main journal sizing. This block is the only low deck he’s ever seen or heard about set up that way. The block was stamped EX 7, so he assumed it was experimental block number 7. The back of the block was marked “stress relieve” so Arruzza assumed it as stress relieved. This engine had indeed been run on the dyno and wear and tear was visible on the rocker gear parts, pushrods and guideplates. Those issues were addressed and the pushrods now have hardened shafts to stop any future wear. The guideplates are now micropolished where the pushrods ride, and have been Casidiam coated as stated earlier.

The distributor is a new old stock Prestolite electronic tach drive race unit plugged into an MSD 6-AL box. The rings are from Childs and Albert– Duramoly 1/16 1/16 3/16 with standard tension oil rings for street use.

Tom Hoover stated the A279 would have made for an excellent high performance race engine due to the light weight, excellent breathing, excellent combustion chamber design and swirl fill ports on all 8 cylinders that fill the cylinders very nicely by the nature of their design. Big block Chevy engines have only 4 swirl fill cylinders and 4 back fill cylinders thus not giving the engine an equality from cylinder to cylinder. Same problem for most wedge –style engines including, sadly, Chrysler’s own 440 and Max Wedge-style engines. Even the small block Chevy has this problem.