The exhaust could either be straight through or bypassed through the mufflers just by removing the gas caps on the ends of the straight pipes.  The Mk1 had the same setup for the noise equals horsepower group. 

So they got it running and ran it on the streets around Cannon's shop.  Ted said that Jim would spin it around three times in the yard and then shoot out onto the street.  An SCCA official came and visited and mentioned that they wouldn't let it race because it didn't have a differential.  They couldn't figure out how to make a differential with this system, so they abandoned the project. 

I'm thinking Chapparel or GT40 

Mid Engine, light weight, aircooled, overhead valve, dual ignition, 1950?  This could have been a game changer.