HEAD-2-HEAD part:3 Promaxx stage 1&2

Promaxx is a brand that grew out of  remnants of Patriot Heads and Alabama Cylinder Head Exchange. They offer heads from stock replacement diesel to aftermarket performance , their products run the spread. Based out of Alabama they are  a family based business with over 30 years experience in racing from bracket racing to ProMod .  The FE heads heads tested below are out of the box examples of their Stage 1 and Stage 2. The Stage2 are CNC ported  on intake and exhaust to increase flow. Offered through many dealers including Jegs , base price starts at $999.99 bare and allows room in your budget to customize to your application. As always they are tested by Dan Rawls at Cleveland Performance Center on a SuperFlow 600 with a 4.250 throat, thanks to Dan and Crew.


                          Stage 1                                                                         Stage 2
            int            lift           exh                                                   int          lift          exh
           144          .200           94                                                   118        .200         94
           174          .300          131                                                  168        .300        131
           218          .400          163                                                  215        .400        167
           247          .500          188                                                  250        .500        191
           271          .600          204                                                  280        .600        207
           284          .700          213                                                  297        .700        219

(Dan noted that with a more aggressive valve job the flow numbers would show even more improvement  on the stage 2)

Here is a view of the combustion chamber
 and under valve throat

Shown here is the Stage 2 cnc ported intake

View of the as cast intake port