Speedway Workshop
 
The Drake 4 Valve Conversion

Bore: 88 Ignition: Magneto
Stroke: 81.7 Inlet Port: 35mm Push Rod operated 4-Valver
Designer: Ed Schafer, Los Angeles, USA

This JAWA conversion was developed by the DRAKE Corporation whose main claim to fame was the fabulous Offenhauser engine as used in the Indianapolis 500 car race, from which the head design was used on the Speedway engine.

The engine was actually designed by Hans Herman who was the Chief designer of DRAKE engineering whilst the owner of the company and Chief engineer was Ed Schafer, who also worked for SRS (Speedway Research and Specialties), and revealed that the 4-valve head was inclined at twenty degrees and pushrod operated.
The engine, tested by American and Exeter star Scott Autrey, became available for the start of the 1976 season and featured a flat piston with 4v cut-out. Mr Schafer noted, "The benefit of our 4v Head is that it bolts on to a JAWA engine with no modifications or machining required. The conversion kit consisted of the following:
Cylinderhead complete with valveguides , springs , rocker arms pushrods.
2 ring forged piston 14 / 1 compression ratio
When you placed your order you sent your cams to be reground and the price of the conversion kit was $ 600.00 US

We would like to thank Bert Sergent from New Zealand who has kindly sent us the following pictures of the DRAKE (Speedway Research) Motor:

 

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