Mopar Max Wedge Cylinder Heads Guide - Size Does Matter

The small, 1.60-inch exhaust valve (shown here) is typical of most 915 or 516 castings. When compared to the 452 casting on the right, the difference is apparent. Cutting the existing seats, or better yet, having hardened seats installed to accommodate larger exhaust valves is a great way to get extra power from closed chamber heads.

This 452 casting shows the open-style combustion chamber common to the '68-and-up big-block Chrysler cylinder heads. These heads had limited potential due to the open chamber design, but made up for it with larger, 1.74-inch exhaust valves.

Casting numbers can be found on the top of the intake runner, as well as the bottom side of the head under the intake ports. The 906 and 452 are the most common open chamber heads, but many casting numbers were manufactured between 1968 and 1978. All of the open chamber heads have similar power potential.

Edelbrock heads, unlike some other aftermarket units, oil the valvetrain through the original passages in the block and don't require extra lines at the rear of the engine. The combustion chamber is a closed quench design offered in two sizes. Also notice the spark plug location is angled toward the exhaust valve, which promotes more efficient combustion.

The Edelbrock Performer RPM heads are available with either 84cc or 88cc combustion chambers. When compared to the open-chamber factory design on the right, the differences are apparent. The Edelbrock heads are a great choice for a street, strip, or dual-purpose vehicles, offering good performance at a reasonable cost.

Indy cylinder head offers several choices for the big-block Mopar enthusiast, including the popular 440-1 cylinder head shown here. We made over 900 hp from a normally aspirated 540-inch wedge with a pair of 440-1s, running consistent 8.90s at 150-plus mph in a 2,800-pound back-halved '71 Duster. Needless to say, we were impressed with these Indy units.

The 572-13 and 600-13 Indy heads have the rocker stands milled down and are machined to accommodate Jesel rocker arms. These heads are the ultimate in wedge performance with power potential up to 1,200 hp in normally aspirated form.

If you want to see how the 572-13 heads perform on the strip, stay tuned. We just finished installing our 572-inch wedge in this '71 Duster and will feature the build and the dragstrip testing in an upcoming issue.