/6 turbo

I suspect, if Smokey's engine wasn't a bit of trolling, it was a homogenous charge compression ignition engine. Very tough to set up and tune, and running past the edge of detonation, on purpose. It definitely wasn't on stock internals, and while he sold the rights to Crane, they never were able to package a kit that your average installer could get working right without being tuned to an individual engine.