Apparently, the acclaim for the Astro I enabled Mitchell to excise his dislike/jealousy of Zora - or maybe he knew it was time to get serious about planning a C3 replacement. Regardless, Mitchell's and Zora's teams worked "together" to create the XP-880 Astro II for the 1968 NY Auto Show.
Mitchell's contribution was a body that continued the XP-819 and Astro I evolution - both, of course, were influenced heavily by the Mako Shark / Manta Ray designs. Unlike the Astro I, the XP-880 was to be a preproduction design so there was storage space, doors, pretty good forward visibility, comfortable cockpit, wheel wells that could accommodate performance rubber and a 43" height.
Zora chose to go with a backbone frame, and a 390 HP Mark IV big block feeding a Pontiac Tempest Transaxle. The center backbone actually contained a 20 gal fuel cell. I'm thinking that they could drive this puppy around OK but attempts to break loose the tires had to be verboten, or spend your weekend replacing that rather fragile transaxle.
Unlike the exotic mid-engine sports cars of the day, the Astro II had the radiator out back. The front trunk actually provided luggage storage. There was also enough storage behind the seats to place a collapsible spare tire on one side. The rest of the cockpit included normal instrumentation, exceptional lateral support, and (because of the Tempest Auto) a sliding gear selector.
The rear hood/fenders/hatch/ rear fascia/clamshell started at the rear edge of conventional doors and ended ... well at the rear of the car. Uh huh. I see all you fellow C4 owners / former owners rolling your eyes. Imagine how heavy this Astro II piece would be in production. Definitely heavier than the C4 hood. Regardless, it provided generous access to the storage compartments directly behind the seating area, the suspension, and the drive train. The big block was turned 180 degrees, placing the accessories (alt, water pump, etc.) farther away from the cockpit and the drive to the transaxle at the (former) front of the 427 engine.
The finished XP-880 weighed 200 pounds less than a production 427 - albeit with the fragile transaxle.
Here you can see how much smaller and lower the Astro I is compared to the Astro II. Proportionately, the Astro II also has wider rubber and a more stable / wider wheelbase. These were concessions that Mitchell didn't have to make on his covert, design exercise Astro I.
That's the next installment, the Indy / CERV III, behind the Astro II in this pic.
Why didn't the Astro II lead directly to a production C4?