BACK

There is a wide variety of people enjoying the benefits of our "Hemi Performance Engineering Head's " , from the private individual to the most competent dealers and performance shops. We feel it's important to clarify some Do's and Don'ts along with specific examples of which cams will or will not be compatible with our heads. First and most important-when in doubt, stop and call us at (708) 656-HEMI.

In most cases, we'll be able to tell you what will or won't fit. Generally speaking, all the name brand cams are compliant with our heads including Andrews Products, Red Shift, S&S, Crane and Screaming' Eagle's Performance Street Cams.

"Hemi Performance Engineering" Kits will accept cam lifts up to .630" (higher lifts can be achieved but must be specified prior to ordering). You need not check the valve to valve or valve to piston clearances. Our heads will accept even higher lifts but, here is where potential problems may occur with "Hemi Performance Engineering" off-the-shelf kits.. For example, the Red Shift .653 lift cam will fit our Big Twin Heads but the Andrews .640 lift cam will not! The reason is that the TDC lift is higher on the Andrews cam than on the Red Shift. However, its our opinion that cams of this nature require higher compression and are intended for serious street bikes or racing applications only. If your cam of choice contains a TDC lift of more than .200" lift, you must specify prior to ordering so that we can assure that your final valve-to-valve is correct. It is the final responsibility of the engine assembler to verify if a particular cam should be used. We repeat-if in doubt, call us!

Timing -Because of our design, we have found our heads require less ignition timing that any other kit you can buy. This is because our heads are so efficient that maximum horsepower is achieved with less timing. So, before you start the bike, set the timing back 2-4 degrees (Note: we are not reducing the timing to prevent detonation it's simply that the "Hemi Performance Engineering Head's" require less timing to achieve maximum efficiency). See installation notes

Once the timing has been established, there is no reason to ever change it. Carb and exhaust changes will not normally have an effect on timing. However, cam changes could effect ignition timing requirements.

Jetting - call with your specific application

Exhaust -Different systems can and do effect carb jetting. We have seen many examples on our dyno where straight pipes or baffles removed have made it necessary to decrease the main jet size using our heads! Only serious racing engines with ultra high compression benefit from open exhaust systems. There is such a variety of exhaust systems that we simply can't discuss them all, but we can say that through our dyno testing we have found that F.A.I.C. exhaust system makes great horsepower and torque numbers for us and that is why we recommend them to our customers. Screaming' Eagle low restriction and White Brothers E-Series also work very well.