ZL1, COPO, L88, SS, RS, Z/28, Z06without context, Chevys mid-century order codes are about as evocative as reading the back of a once-a-day vitamin bottle. Unsurprisingly, the docket of Mecum Auctions upcoming sale of Rick Treworgy's sprawling Muscle Car City is loaded to the air cleaners with these alphanumeric codes, and while its tempting to fixate on the incredible COPO Camaros and SS variants filling up the show floor of the former grocery store, we cant tear our eyes from the rare and semi-obscure 1965 Chevrolet Chevelle Z16 thats up for grabs. As demand for high-performance muscle car variants rose in the mid-1960s, Chevrolet realized the relatively staid Chevelle was at risk of falling behind its contemporaries as the big-block floodgates swung open. The popular small-block 327-cubic-inch (5.3-liter) V-8 was offered within the first year of Chevelle production in 1964. But its maximum output of 300 hp put it behind the competition, particularly as the Pontiac GTOs tri-power 389-ci engine spun out 360 hp and a wicked 424 lb-ft by 1965. A 350-hp RPO L79 327 was made available in 1965, but the 360 lb-ft couldnt match the tri-powers tenderizing torque. Of course, the legendary SS 396 was just a year away, but there was little promotion or fanfareyetfor the forthcoming big-block Chevelle. To ramp-up interest for the future big-block package, Chevy slid the then-new 396-ci (6.5-liter) L37 big-block V-8 into a run of 200 Chevelle SS coupes and one convertible. This new hot rod carried the internal designation of Z16 and was offered primarily to members of the media, Chevy VIPs, and other high-profile individuals the General deemed would effectively promote the big honkin engine package just over the horizon. While the Z16 is more than just a shoehorned big-block, it was all about that engine. A hearty 375 hp and a thick 420 lb-ft made it one of the most potent muscle cars of its day, with each 396 matched to a Muncie four-speed manual transmission. Interestingly enough, though the 396 shared a basic design with the same year's Corvette 396, the Z16s L37 utilized more street-friendly hydraulic lifters versus the Vettes solid-lifter setup, owing to the Corvettes L78 396's 425-hp rating. Elsewhere, Chevelle Z16s were beefed up to handle the extra gumption. The frame was that of a Chevelle convertible, chosen for its additional structural reinforcement. Around back, the Z16 wore a narrower rear axle and upgraded brakes from the Impala along with the customary heavy-duty suspension. Visually, good luck picking a Z16 out from a field of 1965 Chevelles; aesthetic differences were limited to a bespoke black-and-chrome rear panel with untrimmed taillights pulled from a lower-spec variant. A quick indicator of a potential Z16 is the color; whereas a regular Chevelle SS could be covered in any of the 15 paint options, Z16s arrived only in Tuxedo Black, Regal Red, or Crocus Yellow. --> Of the 201 produced, only around 75 are accounted for, making any Z16 that comes to market a noteworthy occurrence. Treworgys Z16 is one of the nicest out there, especially wearing rare Crocus Yellow paintwork. According to Mecums listing, the car is still fresh from a past frame-off restoration and carries documentation stretching back to the original owner. Interested? We thought so, but it wont come cheap. Make sure you register to bid before the Z16 crosses the auction block, as it's currently on schedule for the first day of the sale on January 22. The post Mecum's Upcoming Muscle Car City Museum Auction Features Rare Chevrolet Chevelle Z16 appeared first on MotorTrend .