I misidentified this as a rare 914-6 GT body awaiting drivetrain installation.
Thom Kuby reports this is an even rarer 916,
"...one of apparently eleven built; chassis #9142-33-0014, build #131 0434,
and fitted with engine #632-5022. Painted in Brown Metallic ...

... It was the only 916 painted brown."
See no. 24 for another view.