THE Z11 CHEVY DAYS

Chevrolet’s Quest for Superiority in A/FX and S/S Classes

In a quest to best Chevrolet’s thunder in the top A/FX and S/S classes, special parts and pieces were created. Luckily, there were few secrets in and around Detroit, and Chevrolet had no problem creating its own performance-enhancing pistons, cams, heads, and inductions for battle. Because there were no limitations to what could be created as long as they made the minimum production numbers, GM approved aluminum front-end body components to reduce body weight.

The Secretive Nature of Chevrolet’s Performance Parts

Regardless of what Chevrolet would have NHRA believe, these items were not readily available. In fact, these items could never be found anywhere, and a call to the factory would bring zero response. The General had its own marketing methods, which, for some reason, always resulted in a confidential approach. All the stories you may have heard, along with all those persisting rumors, were just that—information made up by those who either had bits and pieces that never added up to a whole or imagined what they wanted to believe.

Distribution of Rare Parts to Select Racers

As a result of personal contact with past Chevrolet staff personnel, all the information pointed to the fact that these low-volume parts and pieces were either shipped or hand-delivered to only a select few chosen racers. Sure, they went nationwide, and sure, there were a few very involved dealerships that also received a set of parts (or two), but that’s it. The racers obviously thought little of performance history or parts rarity in those days; they all wanted the parts that would get them the low e.t.’s they wanted and a win. Little was known about how the very cars they raced would become so sought-after more than 40 years later.

The 1962 Chevrolet’s Aluminum Components and Their Impact

Those rare engine parts and body components were first seen on ’62 Chevrolets, and that was during mid-summer. Many point to the big meet at Detroit Dragway prior to the U.S. Nationals in Indiana as the first big competition between all makes of powerful lightweight cars. Hayden Proffitt won both events in his new SS/S red 409 Bel Air bubbletop.

The Birth of the 1963 Z11 Lightweight Impala

News clippings revealed that as many as 18 sets of 1962 aluminum front ends were sent to racers as well as an unknown (small) number of 409 top-half assemblies that were labeled “RPO Z11.” Not much more is readily known. In a blink, 1962 was history in the making. In 1963 General Motors approved complete lightweight drag-only Impalas for sale to select racers and anyone else who was at the right place at the right time.

Z11 Impalas: A New Era of Drag Racing

While the 1962 Chevrolet drag cars with their aluminum components and Z11 heads, induction systems, camshafts, and breather assemblies were sold off to second-owners, Chevrolet built 57 Z11 lightweight ’63 Impalas. Sanctioning body cubic-inch limits of 427 were in force, and that’s what the bored and stroked Z11 409 turned into. With a 12.5:1 compression ratio, big rectangle ports, flat combustion chamber heads, two-piece induction, and a pair of Carter AFB carbs, horsepower was rated at 430 at 6,000 rpm. In actuality, if the truth were known, power was more on the order of 500 hp-plus!

The Legacy of the Z11 Impala

Many insiders revel today in that the factory ’63 Z11 Impala was the highest cost, lowest-production Chevy ever. A number of racers bought Z11s thinking that there would be more than 100 sold, so the car would qualify for Stock Eliminator competition. But with only 57 built, the Z11 had to compete in A/FX (where and when it was run) or Modified Eliminator. The classes were called many names, including Factory Experimental (FX), Limited Production (LP), and A/Modified Production (A/MP).

The Popularity of Z11 Impalas in the Drag Racing Scene

These were the most popular cars of their day. When dragstrips had open events for these cars, or when they were hired in for match races, fans turned out in droves and lined the fences. Many would bet race-by-race on the best-of-three matches, and this frenzy would often stack them 10-deep. And not all races were held at the bigger quarter-mile tracks; many raced at small 1/8-mile tracks in back-country locations, and they were extremely popular in the East and especially down in the South. In the middle of the country, these events would be billed as big two-day events, and it wouldn’t be uncommon for the larger, privately held events to showcase over 30 lightweight cars (from all manufacturers) for big bucks in those days.

The Continuation of Z11 History and Its Influence

We first wrote about Z11 history back in 1982 when a fellow named Kirk Wright showed us his completely original ’63 Z11. He also had copies of all-factory documentation and Z11 sub-component part numbers. We even drove his Z11 with mufflers on neighborhood streets. As Chevrolet performance car history goes, we consider the ’62 Z11 program a huge stepping stone from the ’57 fuel-injected 283 Black Widow Grand National stock car program, and one that led to the outrageous ’63 Mark II 427 “Mystery” motor. Add in the ’65 RPO Mark IV big block, and you can see how important Chevrolet considered streetcars and drag racing to be in those days.

The Changing Times of NASCAR and Drag Racing

Today the times have changed, and cars of this caliber are no longer considered essential. NASCAR and drag racing are so sophisticated that private-party racers have little chance of competing on a level playing field. Just look at Pro Stock, and you will plainly see that these cars bear little resemblance to whatever they are supposed to be, and they don’t even bother to model/identify a NASCAR cookie-cutter body. The only thing that keeps a Chevrolet in the winner’s circle today is a mega-buck development program using specially built race-only cylinder blocks and specially cast aluminum heads that alone cost more than an entire Z11 racecar! Oh, how times have changed.

Conclusion: The Lasting Appeal of Super Stock Racers

This is no doubt why yesterday’s news and fables are so popular today, and why old Super Stock racers still can gather a huge crowd wherever they appear. The Auto Builder has a ton of Z11 stories to tell from right out of the good old days, so stay tuned as we drop them on you while we continue to cover an era that muscled its way into the hearts of Chevy-lovers everywhere.