These are great times for Max Wedge fans. Never before have so many cross ram choices been available for your consideration. We’re not talking about obscure swap meet oddities either, we’re talking about foundry fresh castings you can easily buy today…right now. While aftermarket sources such as Indy Cylinder Head offer loose interpretations of the cross ram for all out drag racing, this review is limited to those manifolds that seek to retain the original appearance. Don’t know about you, but half of the treat of lifting the hood on a Max Wedge is having the right look. In a sense, we’re tapping into the past and we don’t want any upsetting visual cues to harsh the buzz, dig?
Before we start this review, let’s remember the hows and whys of ram tuning. In a nutshell, you have to remember that as each cylinder pulls fuel and air during the intake stroke, the resulting column of fast moving gasses has a certain amount of mass. As the piston approaches bottom dead center, the intake valve closes and the column of gasses comes to a sudden stop inside the intake tract. As a result, there is a certain amount of stored energy present as the column stops moving. This energy is present in the form of pressure waves that bounce back and fourth between the back of the closed intake valve and the mouth of the carburetor at something like 1100 feet per second.
Okay, knowing this, the next time the intake valve opens, there should be a pent up wall of gasses waiting to crash the gate and fill the cylinder bore. If you tailor the valve timing just so, and if you configure the intake runner in just the right way, you can take advantage of these naturally occurring resonant waves and get a form of free supercharging. It isn’t like plopping a belt driven GMC 6-71 on top of things, but it’s a proven fact that induction efficiency of as much as 108 percent – that’s 8-percent above atmospheric - can be realized. If that isn’t free supercharging, we don’t know what is. Furthermore, by adjusting the length and volume of the intake runners, you can tune the incoming “supercharged” rush to occur at specific engine speeds, thus boosting cylinder pressure and torque in harmony with the selected rpm point.
Back in 1960 when Chrysler unleashed the two piece long-ram induction systems on full size C-body models, the goal was improved low and mid range torque for quick stop light getaways and rapid highway passing. To achieve this, the runner length was 30-inches and the resulting torque spike occurred at 2800 rpm and carried on through about 4800 rpm. It was great for moving two-plus tons of luxury liner, but the long branches choked flow after 5000 rpm so the top end performance suffered.
But when Chrysler got serious about entering the Super Stock fray in 1962, they knew top end breathing efficiency was more important than passing power on the highway and so they reduced the runner length to 15 inches. This tailored the resulting one piece cast aluminum manifold to tune at 5400 rpm. The Max Wedge was born. Truth be told, as designed, the original cross ram is very well suited to a 413 cubic inch engine spinning at 6500 rpm. When they upped displacement to 426 in 1963 and 1964 to take full advantage of the 7 liter cap imposed by NASCAR, the manifold still worked great. But as racers got creative and started using 488-cube stroker cranks and stepping up the cam and valve springs for 7000 rpm rev capability, the cross ram quickly got in the way and choked power.
With the 426 Race Hemi due on the scene for 1964, factory Max Wedge development ground to a halt before further improvements could be made. Word is that Barney Navarro – perhaps with assistance from Chrysler - cast some wild cross ram intake manifolds with four Carter AFB’s in place of the usual two. Max Wedge guru Bob Mazzolini supposedly has one of these crazy quad quad Maxie manifolds. But Hemi fever was on and after mid-1964, the Max Wedge pretty much slipped into obscurity for the next four decades, a swap meet relic.
But in recent decades, more and more guys are rediscovering the Max Wedge and want to tap into the crazy mystique of the Orange Monster. Simply put, if you are doing a Max Wedge clone, you simply must get a cross ram. There is no place for single quads – even though many are capable of outperforming the mighty Max Wedge - all other things being equal. Sometimes looks are more important than raw performance. Let’s review some of the current offerings and also take a peek at some rare old behind the scenes Max Wedge development pictures.