Hemi Valvetrain And Head Upgrades - Superior Solutions - Tech:

After even the best aftermarket Gen III Hemi valvesprings failed, Joe Jill realized the root cause was the Hemi's beehive valvespring configuration. Despite the slight advantage of having lower mass than conventional straight springs, there's no arguing with the epidemic of failures. The solution is a conventional straight spring. But as we see in this photo, the underside of the Hemi's cast-steel rocker arm is designed to work only with 0.900-inch-diameter beehive-style retainers and interferes with larger retainers (pen points). This is as far as the rocker will drop before hitting the retainer. Clearly something must be done.

Here's a shot of the new Manley titanium retainer and Chevy Gen III (LS1-type) valvespring in place on the Hemi. Notice how the rocker arm-to-retainer contact problem is totally solved. Though the lower retainer placement does alter valvespring installed height and increases open and closed spring pressure, the difference is under 20 pounds. Because the custom valves retain the OE valve length, the Hemi's excellent rocker arm geometry is not affected. Because any 1.290-inch-diameter Chevy Gen III valvespring now fits the Hemi (right out of the box), you have a nearly unlimited selection to choose from, plus unquestioned spring durability.

And speaking of custom valves, Superior Automotive offers custom valves (right) for 5.7 Hemi owners looking for extra flow and power. Fred says, "There are probably 1,000 5.7 owners for every 6.1 out there, and while the 5.7 does have smaller ports, we can make 'em run." The first step is replacing the stock 2.00/1.55-inch valves with the 2.08/1.600-inch combination used in the 6.1. This change alone will deliver a 7-percent flow improvement and can be performed without the expense of changing the valve seats. With maximum porting, the 5.7 head can flow within striking distance of the stock 6.1. Since 6.1 heads are currently on restriction from Chrysler (i.e., only available for warranty claims), lots of 5.7 owners bring their heads to Superior for porting and valve changes. Superior is also developing a 383 stroker kit for the 5.7 that'll be ready as you read this.

While the top end of the Superior/Manley valve is custom, the bottom end features the same excellent swirl polish treatment, beefy margins, localized stem diameter reduction, and one-piece stainless steel construction as regular Manley performance valves. A stock 5.7-sourced Chrysler valve is shown on the left for comparison. Superior can supply these special valves with stock 5.7 (2.00/1.550 inch) or 6.1 (2.08/1.600 inch) head diameters, as well as custom 2.100/1.650 sizes.

In a move likely intended to cut costs, Chrysler 6.1 Hemis use these goofy wire retainers to help keep the rocker arms in alignment with the valve tips and pushrods. Fred says, "These parts are pure Mickey Mouse. The rocker shafts have no receiver grooves so the retainers usually migrate out of position during operation. When they do, the pushrods are the only thing keeping the rocker aligned." Ironically, the bread and butter 5.7 Hemi uses a slightly more positive stamped steel sleeve to do the same job. It's better, but not ideal.

Superior offers this rocker arm spacer collar kit (PN HVT-1) to ensure accurate pad-to-stem alignment and prevent side loading on the pushrod tip. It's machined from 0.125-inch-thick seamless 6061 aluminum tubing and comes with an assortment of hardened steel side shims to allow perfect alignment. It fits all 5.7 and 6.1 heads and increases valvetrain stability. It's a good upgrade for stock and modified engines alike.

Before he devised the Chevy valvespring solution, Joe says, "The constant parade of failed beehive valvesprings called for a unique tool for fast in-car spring replacement." If Joe looks familiar, it's because throughout the '60s, he was a regular fixture in many east coast car magazine tech articles. At the time, his shop was Speedwin Engineering, home to numerous Race Hemis, including factory-issue '64, '65 and '68 Super Stockers. Pick up a vintage copy of Hi-Performance CARS, Super Stock & FX, or Speed and Supercar, and you'll see Joe's smiling face.

Hand fabricated from steel, the trick valvespring removal fixture allows in-car valvespring removal and installation. Just roll the crankshaft so the piston is at TDC and pressurize the cylinder, then go to work. Be sure to leave one spark plug in place so the cylinders hold air pressure. Remember, these new Hemis have twin plug ignition.

After the rocker assembly is removed from the engine, the fixture bolts to the head, and the threaded screw-jack is used to compress the valvespring so the locks can be plucked free. Then you unscrew the jack, and the retainer and spring are removed. Before he devised this solution, Joe says it took two hours to change a single valvespring, more on the cluttered passenger side of the engine. With the tool, all 16 springs can be changed in one hour. If you want one, contact Superior Automotive and talk to Joe.