Edelborck's Performace Heads - All Hail The Victor - Tech

Someone was actually crazy enough to "loan" us a Performer RPM and a Victor head. our rolling bandsaw made quick and clean work of cutting the heads into pieces. Yes, we removed the hardened valve seats from the heads before we cut them. It almost seems a shame to cut up perfectly good Edelbrock heads, but the quest for knowledge has no boundaries.

Let's start by showing some of the most obvious external differences on the Victor head. First, you'll notice the integral spacer that is part of the casting on the intake-manifold face. At .950-inch thick, it eliminates the need for separate manifold spacers. Unlike separate spacers used in some other cylinder head applications, Edelbrock has ensured perfect intake port alignment with plenty of material for future horsepower production.

Here, you can see the difference in the height of the RPM's and Victor's valve cover rails. This gives us several advantages. It raises the valve cover away from the rocker assemblies so high-lift cams, combined with thicker and stronger roller rockers, can be used without hitting the valve covers. The raised rail also keeps the oil farther away from the valve cover gasket to reduce any possible valve cover leaks. With Edelbrock's precision CNC machining, perfectly flat rails ensure a positive leak-free seal.

The Victor's noticeable height increase is evident when placed next to an RPM head on a flat surface. By increasing the valve length by .400 inch and raising the exhaust and intake runners, the Victor grows significantly in the vertical dimension. (Holes drilled into the side of the RPM head were for verification of thickness from a previous experiment.)

We can see quite clearly the Victor's raised (.650-inch) intake port is head and shoulders above the RPM head's intake port that, by design, has been left in the stock location. notice the port floor of both cylinder heads and the inside port wall on both heads. The Victor, with its raised floor and straighter walls, is a high-flow, big-power cylinder head.

The exhaust ports also received the same elevation treatment. Edelbrock raised the exhaust port by .250 inch for greatly improved exhaust flow. Don't worry about exhaust headers; tti (Tube Technologies Inc.) makes headers that fit these heads for all popular Mopar makes.

Unlike the RPM head, which still uses the stamped-steel valley tray to seal the lifter galley, the Victor head uses a flat, stamped-aluminum valley that is sealed on the beveled edge (shown here). Since a stamped valley tray is not used, separate gaskets are needed to seal the intake to the heads. This virtually eliminates any chance of vacuum-induced oil leaks, or valley pan replacements if the manifold is being removed regularly.

The engineers at Edelbrock went to great lengths to increase the airflow requirements of the Victor head. By lengthening the intake and exhaust valves by .400 inch, they were able to increase port volume and enable the end user to use large-lift race cams.

Here, we can easily compare the two different chamber designs-the RPM head is on the left; the Victor is on the right. Even though the RPM head, with its 84cc chamber, is vastly superior to and far more efficient than any old iron Mopar head, the Victor takes it even further with its 75cc combustion chamber.

Here's a close-up shot of the 75cc closed-chamber head. Notice the "kidney bean" shape. Edelbrock calls this their Dual Quench chamber; they are trying to take advantage of an unshrouded intake valve and a similar exhaust valve. A smaller combustion chamber means a smaller piston dome, which equals better flame travel, which makes it more efficient, and that all equals more horsepower. Let us also take note of the valve size: 2.200-inch-diameter intake valve and 1.81-inch-diameter exhaust valve. That is a .0471-percent increase in intake-valve diameter. That's almost 5-percent over the RPM head in valve diameter alone at the valve seat.