When the topic turns to big-block Mopar wedge power, invariably Indy Cylinder Head is a key part of the conversation. Having pioneered the development of high-flowing cylinder heads for the big Mopar, Indy played a major role in popularizing the performance potential of these engines. The Indy strategy centered upon new aluminum castings in the days dominated by undersized stock iron, opening the wedge’s potential. The voluminous new ports afforded by the Indy heads were made possible by using substantially longer valves than the compromised OEM units, gaining the much needed room to incorporate high-flowing ports in their cylinder head design. Indy’s original cylinder heads revolutionized Mopar big-block wedge performance, bringing real horsepower to the masses. From those beginnings, Indy has been continuously expanding its big-block Mopar product line to include virtually everything needed to build a complete aftermarket wedge engine.

This is exactly the project we embarked upon last month (“The Indy Maxx 500, Part I,” May ’13), when we detailed the building of a 500-inch low-deck Mopar wedge bottom end based upon an Indy Maxx aluminum block. Rather than look to build an engine to show maxed-out numbers on the dyno, our goal with this engine is to build a reliable and street-capable powerhouse wrapped in a lightweight package that weighs about the same (or close to) the all-iron slant-six in our ’68 Valiant project car. To this end, high torque, moderate rpm, and conservative cam specifications would provide reliable street power that will perform over the long haul with a minimum of hassles. In fact, Indy’s engine builder, Ken Lazzari, worked hard to run as little cam as practical without unduly hampering output. When the short-block was assembled, the cam selected was a COMP solid flat tappet grind with just under .600-inch lift, and 245/250 degrees duration at .050-inch lift. Lazzari was looking to make the most of the power curve while keeping peak horsepower rpm right around the 6,000 rpm number.

Big-Block Top-Up

Keeping in mind the intended powerband and desired operating rpm range, Lazzari selected Indy’s 440 EZ-1 cylinder heads. The EZ line of cylinder heads are differentiated from other Indy big-block heads by a standard exhaust port location, in contrast to the raised exhaust of the other Indy offerings. The Indy EZ head configuration relieves clearance and fit issues that can arise with most commonly available headers, especially when the big-block wedge is shoehorned into the tight confines of Mopar’s popular A-Body vehicles. The EZ series of heads come in several variations, with the basic 440-EZ version featuring as-cast ports, with a 270cc intake port having the standard production big-block port window. The 440 EZ-1 steps up the specifications with the intake port window CNC machined to the Max Wedge dimension, as well as additional CNC work in the bowl for improved flow. Indy also offers fully CNC-ported EZ heads, with the 295cc “Little Easy,” and the offset rocker 325cc “Big Easy.” With our moderate rpm goals and relatively restrained cam timing, the 275cc 440 EZ-1 was the practical choice.

Our completed short-block was built with Diamond full dish pistons, resulting in a compression ratio of 10:1 with the 75cc chamber volume of the EZ-1 cylinder heads. The heads were assembled by Indy with a set of COMP dual springs providing 140 pounds seat load and 375 pounds at full lift, using COMP steel retainers and 10-degree locks. A Fel-Pro number 1009 head gasket clamped by a set of ARP bolts secured the heads to the deck, as our 500ci low-deck wedge entered final assembly. With the cylinder heads in place, the valvetrain was completed with a set of Indy ⅜-inch pushrods, working a team of Indy/T&D shaft-mounted 1.6:1-ratio rockers.

With the Max Wedge intake port configuration, intake manifolds for the standard big-block wedge will not fit the enlarged port window. There are, however, a wide range of intake manifolds available specifically for the Max Wedge, including an excellent high-rise single-plane from Indy. While this Indy single four-barrel manifold would be hard to beat from a strict performance perspective, we were looking for something just a little bit more unique for our application. Indy had exactly what we were after with their new Mod Man modular intake manifold system. The Mod Man arrangement uses an open plenum base in tandem with one of four available top plates to provide a range of possible inductions. Top plates can be had in single four-barrel, inline dual-quad, three two-barrel “Six Pack,” or supercharger configurations. For our street wedge, the single four-barrel unit would have been satisfactory, but we went with the dual-quad arrangement to significantly increase the underhood appeal of our engine combination. The Mod Man inline dual four-barrel top plate readily accepts a pair of Edelbrock Performer Series carbs. Given that Mopar showcased similar AFB-style carbs in their factory inline dual-quad Hemi muscle cars, as well as in earlier dual-quad wedge applications, the Edelbrock carbs were the natural choice for our wedge build. Indy spec’d a pair of Edelbrock #1404 500-cfm carbs, along with Edelbrock’s dual-quad linkage kit. With the heads, valvetrain, and induction system in place, the finishing touch was a pair of Indy cast-aluminum valve covers.