Whether building an engine from scratch or modifying the engine already in your car, there's no doubt that choosing the right cylinder heads for your combination can greatly affect the horsepower and torque your engine will make. For all-out race applications, it makes sense to top your small-block with a set of high-flowing, big-port aluminum cylinder heads, but your budget better include the necessary cubic inches and hardware to make them work properly. Alternatively, you can keep the stock cylinder heads on your engine, but you'll certainly be sacrificing power and durability as considerable improvements to small-block cylinder head design in recent years. Thankfully, Racing Head Service (RHS) and Indy Cylinder Head have teamed up to develop the new 360 X line of cast iron cylinder heads, offering several distinct advantages over factory designs.
Looking for a powerful and economical head for your Mopar small-block? RHS teamed up with Indy Cylinder Head to develop the new 360 X Cylinder Head for both Magnum and LA applications, and it might be just what you need.
There's no doubt that some of the factory Chrysler cylinder heads like the X and J castings for the LA engine performed well when they were produced, and the Magnum cylinder head makes great power even in stock form on small-blocks of any size. Seeing the benefits of these designs, RHS and Indy engineered the best attributes of these heads into the 360 X line of cylinder heads, developing two distinctly similar castings in terms of port design, port volume, valve size, and chamber design. RHS's LA-X casting is a direct bolt on replacement for the LA style small-block, and the MA-X casting is a replacement for Magnum engine applications. RHS was nice enough to send us a pair of the LA-X versions so we could give you the first in-depth look at this new product.
Both the LA-X and MA-X castings feature 179cc intake runners and 67cc exhaust runners, and feature a 62cc combustion chamber. RHS also casts these heads with extra material on the deck surface so they are easily angle milled if necessary to increase compression. Both the 360 X castings come with a multi-angle, hardened intake valve seat cut for a 1.92 inch valve, and a hardened exhaust valve seat with a radius cut for a 1.65 inch valve. RHS and Indy improved the valve guide design of this head, and also designed a highly efficient water jacket to help prevent hot spots. LA-X castings use the standard small-block intake and rocker gear, the appropriate valve cover bolt pattern, and have accessory bolt holes on both ends of the head. The MA-X versions are designed for use with Magnum intake manifolds and pedestal mounted rockers, with pedestals that are cast large enough to drill and tap for 7/16-inch studs and guide plates.
The LA-X version of the 360 X head has rocker-shaft stands cast in just like factory heads. The exhaust ports feature both standard and W-2 bolt holes as well. Magnum versions have pedestals that will accept 7/16-inch studs.
So if you're looking for the right combination of moderate price, and horsepower potential in the 400 to 550 range, the 360 X heads from RHS and Indy Cylinder Head just might be the right way to make your small-block not seem so small.
