02/21/05

Subject:    Rocca Chevrolet "Interim" Cross Ram Manifold Assembly

Part Number(s):      Upper Half – PN# 3941130, Date code - None

Lower Half – PN# 3941126, Date code - None

 General Description: 

 Chevrolet Cross Ram Manifold Assembly

    Chevrolet Cross Ram Manifold assembly consisting of lower and upper manifold halves, stamped steel heat (oil splash) shield, oil fill tube, thermostat housing and coil bracket. All components are original Chevrolet built or distributed. All appear in excellent condition.

·            The manifold identified on these pages is consistent with a one-off Cross Ram unit cast by Winters Foundry for evaluation by Chevrolet as the final configuration for production. For this reason, it still considered to be in the prototypical stage.

·            It represents the state of the final configuration as presented for evaluation. Having the correct production part numbers, but without the one detail common on all actual production pieces that followed. The casting dates that are typically used for quality assurance and to maintain batch records are absent.

            The lack of casting dates on both the top and bottom halves of the manifold in combination with the appearance of production part numbers is the identifier that places this unit as the interim configuration (state between Prototype and Production) for production approval.

   After Chevrolet received this evaluation casting, conditional approval was given and Winters went into full production with several revisions as follows:

Ø            The stamped steel oil splash shield was dropped from production as it was demonstrated to not be necessary – This would be the last manifold to be fitted with a plate.

Ø            The part number on the lower half of the manifold was to be removed from the underside and re-placed on the front intake runner so it could be seen when installed.

Ø            The water jacket was reconfigured and the angle of the heater hose take-off made less acute.

Ø            All components that followed had casting dates as a means of Quality Control.

Engineering Usage:

    Evaluation of components within Engineering consisted of a visual inspection as well as a functional assessment for form, fit and function and was gauged against performance expectations and pre-specifications set forth by Engineering. Therefore, it would have been fitted and run on an engine dynamometer within the Engineering’s Product Development engine test cell.

            In addition, it was not unusual for a pre-production prototype or evaluation piece to be pressed into service due to the high demand and short supply of these components.  Often times Chevrolet Engineering and Product Performance would send out what they had on hand to racers/combines who were considered “insiders”. Many of the parts processed through the ‘back door’ were pre-production pieces or prototypes that were clearly marked as such.

     Based on the timing of sequences and the state of configuration, it is a certainty that this was the Cross Ram unit used on Engineering’s Technical Evaluation Camaro and/or the later 1969 Cross Ram JL8 Press Car in addition to being used for press evaluations.

 Historical Importance:

• This research attempt represents the successful and comprehensive documenting of a significant prototypical race bred Chevrolet development. A works in-progress touched by the greatest engineering talents in the world. An effort that changed the course of racing history and facilitated the most successful automotive marketing strategy for Chevrolet to date by helping capture the prestigious SCCA Trans-Am Series Manufacturers Cup for two consecutive years.

• In particular, this Cross Ram Unit holds a special place in the development of the Cross Ram concept as it represents the final stage before production. Essentially having the highest level of development prior to going into service as Chevrolet Heavy Duty cataloged components with full production numbers as evaluated by the very designers who conceptualized it. 

Photographic Documentation