As a limited use street engine, it is still expected to run hard when called upon. The pistons are actually for a normally aspirated, Chrysler Hemi, injected A/Fuel dragster combination (see photo lower left). The minimal dome provides the desired 9.5:1 compression ratio and the upper ring grooves are configured with horizontal gas ports to improve ring seal. Because of the anticipated loading, these dragster pistons have broader skirt contact with less ovality, hence they are well suited for a turbo application.
Working closely with Duttweiler, racer Lyle Larson helped spec the piston combination. CP techs noted that the requirement almost exactly matched their A/Fuel dragster pistons for injected Chrysler Hemi's that run low 5's at 275 mph. The domes ideally matched the chambers in the Pond aluminum cylinder heads. Because these pistons are made for aluminum rods which are wider than steel rods on the pin end, the pin bosses are spread too far apart. This could compromise piston stability and place additional bending loads on the pin. To correct this, Carrillo made a special set of rods that are wider on the small end to match the dragster pin bosses.
To accommodate the required valve reliefs and high thermal environment, the ring pack is located farther down the piston and the top ring grooves are fitted with horizontal gas ports to ensure optimum ring function. The top ring grooves are hard anodized to protect against micro-welding and the skits are treated with an anti-scuff dry film coating.