07/15/05

Subject:        Chevrolet/Traco ZL1 Prototype Engine/1969 Camaro - Part I

Part Number(s):     Block Cast # O-294550, Date code – None 
                                   1969 Camaro - VIN – 124379N597580, Date code – 02B

Historical Perspective/Overview – General

Chevrolet Aluminum 427 Cuin Engine – Can-Am and ZL1 configurations

Chevrolets disappointment over the results of the 1966 Can Am series and the lack luster performance of the 327 prompted the “advanced thinking” which initiated Engineering’s development of the all aluminum 427. 

            Additional horsepower would be required to re-gain the competitive edge in the upcoming 1967 Can-Am season. The problem was that the 327 had reached the “end-development” stage and only more cubic inches would get the job done.  The Iron 427 was available and was demonstrated to be highly competitive in NASCAR - but the additional weight in the small Can Am chassis was a consideration that could hold it back. Since Can-Am had no restriction on production derivatives, materials, induction types etc., it was conceived by Engineering that experimentation using cast aluminum in limited production was feasible study for the 427.  

The success of the experimental program gave rise to the “Can-Am” Aluminum 427 which had its debut in the 1967 Daytona Continental Can-Am in the engine bay of the Chaparral 2F. The Chaparral immediately went on to set a record for the fastest lap and it held great promise for the series.  As it turns out, it was one of the most successful race engines of all time.

The Aluminum 427 engine became available (in theory) over Chevrolets Parts Counters, and carried an “O-Dash” Prototype (Interim) Casting/Part Number. Of course, availability to the general public was curtailed in accordance with Chevrolet’s policy of keeping “special parts” in the hands of a select few, and therefore Product Performance Groups “Back-Door” policy was in full effect. 

Most of the Can-Am engines were built up inside engineering and sent off to Traco for Penske's and McLaren's use during for the  ‘68-‘69 seasons. The Production Engine Group took over assembly and the engine finally reached regular production for consumer consumption after much corporate debate in 1969. It was made available for the 1969 Corvette and Camaro as Regular Production Option (RPO) ZL1 in extremely limited quantities.  These engines have regular GM production numbers as opposed to the prototypical O-Dash numbering system used on the experimental Can-Am engines. 

Aluminum ZL1 Prototype 427 - Subject

General Description:

             Chevrolet Aluminum ZL1 Prototype 427 engine assembly consisting of; engine block, heads, intake manifold, carburetor, distributor, headers, and all internal and peripheral components that constitute a fully functional engine. All major components are original Chevrolet built or distributed with the exception of those identified in the component break-out that follows. All components appear in excellent condition and the engine is running in full race tune.

 The Block

• The block identified on the cover page (casting # O-294550) of this report and the subject of this document is consistent with the prototypical Aluminum 427 at the stage immediately prior to the release of the Production ZL1.  It represents the final and accepted configuration developed for production ZL1 build. 

• It is easy to distinguish this later state of build from the earlier Can-Am blocks as it uses the wet sump oiling configuration, has a mechanical fuel pump boss and unique and specific identifying cast numbers and build stamp.

      This unit is one of the few that were sent to Traco directly though Engineering for further development and evaluation. It is stamped on the engine pad as follows:  

 

           The above stamp is consistent with Traco’s unique identification system. The L.M. 427^…001 identifies it as the first Aluminum 427 developed for Lothar Motschenbacher. The 53-Y is a typical Chevrolet Engineering stamp that corresponds with a specific assembly build specification. 

            Once at Traco, the engine was torn down and blueprinted to exact Can Am specifications for use in the 1970 Can Am series by Lothar Motschenbacher. The engine was set-up in the bay of the #11 Mclaren M8B “Low Wing” Can Am Race Chassis as driven by Motschenbacher.

         The Vehicle history is as follows: The BM8A/2 McLaren Can-Am sports car was first built in 1968 at the McLaren Factory in England and was the official team car for Denny Hulme to race during the 1968 Can-Am Championship series. At the end of the 1968 season this car was altered and rebuilt using the original tub and upgraded to the Highwing M8B car and became the teams spare car for the 1969 Can-Am series. 

            Throughout the 1969 season the American driver, Dan Gurney, also raced it for the McLaren team. At the end of the season because of problems with his own car, Bruce McLaren drove this actual car in the final race of the 1969 series and thereby won the coveted Can-Am Championship. The car was then sold to Lothar Motschenbacher.

             Lothar had Traco build the subject aluminum 427 for the chassis and raced in several events quite successfully. Shortly thereafter, he badly smashed the race car during a race. Denny Hulme and Goodyear approached Lothar and proposed to make up a promotional "Display Car" from the ruins. Research, photographic evidence and discussion with Lothar confirmed that this was done from a combination of McLaren parts, utilizing the tub BM8A/2, the body from an M8D car and a “dummy” engine/trans replaced the Traco prepared engine. This vehicle was used as a display extensively in the USA and eventually went to New Zealand and was handed to MOTAT in 1978.  The engine went on to see more Can Am racing in subsequent Mclaren/Motschenbacher cars. 

Engine – Current State

 The current state of the engine is as follows:

            The engine now resides in the engine bay of a 1969 Camaro (description of vehicle to follow) and is in magnificent condition. It is in a full-race state of tune, specifically set-up for Drag Racing. Estimated at 600 plus HP. Major engine components are as follows:

                  §         Aluminum block as identified above

§         Heads are Chevrolet Aluminum, PN #396074. Air Flow Research extensively developed these heads.

§         Intake Manifold Chevrolet PN #393318

§         Holley Carburetor List # 4780 – Altered

§         Aluminum Water Pump # 3975928

§         Cam - Unknown

            The state of tune and peripheral component use changed several times depending on its intended racing use. Initially, it was set-up for fuel injection and later changed to the normally aspirated configuration it is currently in to fit within in the stock racing classes.

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. 

• In particular, this Prototype Aluminum ZL1 Engine holds a special place in the development of the ZL1 as it represents the final stage immediately before production. Essentially having the highest level of development prior to going into service as Chevrolet Heavy Duty cataloged components and as regular Production as RPO ZL1. 

• The importance of this engine cannot be overstated as it was developed specifically by Engineering and Traco to compete in Can Am events by one of the most illustrious race drivers of our time, Lothar Motschenbacher. 

• The history of this engine is exceptionally spectacular as the trail begins inside Chevrolet engineering - extends out to to the most famous engine builder in the United States (TRACO) and then onto compete in the the most competitive race series of the time (Can Am) as  campaigned by Lothar Motschenbacher, who was one of the top drivers of the series. 

• I personally cannot think of another single engine that has a more significant documented pedigree than does this, or one that was touched by as many famous and talented personalities in racing. 

 Photographic Documentation

PART II - 1969 Camaro in which this engine resides

Copyright Wayne D. Guinn, 2005
All Rights reserved, No portion of this report
may be reproduced without the express permission of Guinns Engineering