That engine was not developed completely in house, as you said it proved too costly make a long run at it, and consequently never made a long run at it. I had the ZR1 in mind, but it was too rare and short lived to say that GM had success with it. Like I did say, if you read my post, the car would cost 30k more than a standard Vette and no one would go for that. Also, Honda had VTEC long before Chevy even considered producing the ZR1, so to even consider a ZR1 cutting edge technology would not be true. Yes, it was very cutting edge, compared to any other domestic at the time. And even to an extent advanced for domestics today. It just shows how far they are behind. The rest of the world is getting same performance with half the displacement, twice the fuel economy, and 3 times the reliability. That's engineering.