Gene has been modding cars since he was a teenager. Probably '58 or so. I've seen pix of his first attempt and it was wild. A 30-something Olds or Buick chassis with a front seat, a doghouse, a steering column and wheel and a gas pedal. He didn't figure it would ever go very fast, so he didn't bother with brakes when there were so many trees available to just run into.
He did a lot of customization of Honda 600's for a dealer in Mission Viejo, back in the 70's. He was much more of a Hot Rodder, back then.
When I first met Gene, he had a '46 Willy's Jeep with a Chevy 350 and Jerry cans for gas tanks, right under the front seats, A '64 Chevy van with a Chev 350 where the 230 used to be, a '73 MB 300D which he had un-dieseled and swapped in a Ford 302 which he hand-fabricated over-the-top exhaust manifolds, they literally went up, mated with the headers over the intake and dropped down behind the carb and across the top of the tranny.
Gene has always resisted conventional thinking
Anyway, he also had a Datsun 260Z and an Olds Cutlass diesel wagon.
At the time he also had two teenage daughters and a wife sharing the cars, so he only had one extra.
He has always purchased used cars and either fixed them and sold them or used them for his next project. If you have access to enough old auto magazines you could find pictures of his '39 La Salles (He owned 2)his narrowed Lincoln, mid 80's, his '64 Chevy van made it to the centerfold of Truckin' magazine when it had a Cadillac 500 under the engine cover.
I'm sure he's done many projects I never saw.
As for his eco-vehicles, he has been building them for a while. You've seen the VW rat rod truck before he really narrowed the rear end and lowered the roof even further. He actually went so far as to turn the thing into a three-wheeler, but it displeased him, so he killed it.
The Geo has gone through so many rebuilds it makes my head spin. He's had assistance from some folks at Cal Poly. They helped him design some under-effects things that help keep the rear end on the ground. At one point, he had contoured so much lift that the wheels would lift up and even the effect doohickeys didn't help.
Gene has reconstructed the computer chip to his specs and that's one part he doesn't bother telling me too much about. He's obviously doing something right.
The Geo clocked 166 mpg at the TAC National 50 Mile Road Championship in 2014.