Bill Johnson's GT6 is powered by a Ford 302cid V8(as recorded by Dan Masters)
More details... well since I just purchased it I haven't really had an opportunity to go over it really closely yet but here are a few more things I didn't mention. The engine "appears" to be a '79 302 2v, but I havent gotten in with a mirror to look at the engine number and the original build tag is missing. It has a set of hand-made exhaust manifolds on it which look sort of like 289 Hi-Po manifolds and dual flowmasters, so lots of rumble. I said that the rear is a 9", the suspension is a 4 bar setup with a panhard rod and coilovers which are adjustable for both height and damping. The coilovers are kinda crusty from sitting in the damp weather here so I'm not sure what brand they are. Future plans are to rebuild the front suspension and upgrade the springs and dampers and swaybar, go through all the rear linkage heim joints (kinda klunky at the moment..), get larger front brakes and convert the rear to discs. Then once thats done I'll look into making more power and possibly converting it over to a T5 since I'm not a big automatic fan. I teach high-performance driving for the Audi Quattro club (amongst others) and have been involved in racing (road racing/autocross/karts) for about 20 years and my plan is to use the car at track events where I'm teaching and time trial type events... basically anywhere they'll let me on a track.
Thanks for the great website Dan, if you have any questions feel free to let me know. One thing I am looking for is wider fenders... I've seen GT6's running in SCCA with way wider fenders, just haven't found someplace that sells them.