Brent,
I just pulled that off the website that had a "Cobra Kit" sound file. As far as I know, it could be anything, so it's not really an answer to your question. I just thought it might keep you entertained until you fire yours up.
http://www.classicchambered.com
I think the Cobra belongs to these folks;
Kinetic Racing Engines, 38664 Webb Dr., Westland, MI. 48185.
(734) 595-7593. Contact: Chris Gesek.
Engine builders, Cobra Kit Car builders, distributor.
Brad