The Camaro Z-28 is of course another one of those cars that became legendary and perhaps the most iconic of the muscular pony cars. But it was never intended to be primarily a drag strip or red light terror; instead its initial purpose in life in 1967 was to qualify it for the new SCCA Trans Am Championship circuit, which had a 5 liter displacement limit.
That was mighty easy for Chevy to meet: just take on of its 365 hp 327 Corvette engines as sold in 1964-1965, and substitute a 283 crankshaft, to yield the requisite 302 cubic inches. That’s really all it took to create what became the ultimate gen1 small block engine, one rated at 290 gross hp, but actually making some 350 or more. And the actual T/A racers were making 450 or more. All with parts that had been around for years; decades even, in some cases.
The only problem was that its torque didn’t really kick in until some 4000 rpm, which is why it wasn’t so ideal for the street, but by shifting it at 7500 rpm, it was a veritable giant killer, as well as a bargain-basement American Ferrari.
The key to power is breathing, and the Chevy small black started out life back in 1955 with better lungs than average. And they got only better with time, as its heads sprouted ever-larger valves and ports, and those valve were actuated by ever-wilder cams, and were fed by ever larger carbs (or fuel injection). The ultimate heads were the ones with 2.20″ intakes and 1.60″ exhausts, first intended for the still-born 1961 315 hp FI 283, and then used on the 340, 350, 360, 365 and 375 hp versions of the 327. The cam was a version of the “Duntov 30-30”, in this case the same one used in the ’64-’65 365 and 375 hp 327s. And the aluminum intake and Holley 780 cfm four barrel were also used on the 365 hp 327.
Why would a smaller displacement version of that engine (365 hp 327) make almost the same amount of hp? Because the flow of the heads are the limiting factor, and a shorter stroke engine like the 302 can then just wind higher to make essentially the same power. That affects the torque and power curve, and necessitates the 7500 rpm shift points (it could be wound out to 8000 rpm, but to no better effect).
The R&T test car also had the “official” dealer-installed tuned tube headers, a recommended option to help uncork every one of its potential ponies.
R&T was known for its conservative (read: slow) acceleration test results, an issue they fixed in 1980, which then made their results comparable to the rest of the buff books. Also, they were forced to use 7000 rpm shift points because the clutch was acting up, refusing to re-engage above that engine speed. Nevertheless, they still got the Z-28 down the drag strip in a respectable 14.9 seconds @100 mph. And from 0-60 in 6.9 seconds. Other did better, but that 100 mph through the traps in the quarter tells you it was making some serious power. Top speed was a brisk 142 mph.
Interestingly, the Z-28’s suspension was not significantly different than other V8 Camaros, with the same front spring and anti-roll bar as a base Camaro. The rear springs were beefier multi-leaf units. The resulting handling was very good: “a stable, near-neutral car that has no trouble setting excellent lap times around any reasonably smooth course”.
The one bitter pill was the steering, as the optional power-assisted unit as tested lacked feel. The manual steering would have been a better choice for the hard core speed demon. The brakes also acquitted themselves quite well, except for the usual front/rear proportioning.
R&T summarizes by pointing out that the Z-28 was a bargain at the price, offering blistering acceleration, commensurate handling, seats for four, and a top speed of 142. The only downside was its “tractability”. But then the same could be said for a Ferrari GT of the time too, right down to the 7500 shift point. No wonder the Z-28 became such a legend.
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Great read, thanks! I wonder how well an O/D unit would have coped. A perfect solution for the high revving 302.
It’s the only 302 I have any interest in.
The 302 is the engine displacement I always forget when I’m trying to list the ten(!) small-block engine sizes that Chevrolet produced from the same basic block.
And for bonus trivia time, was there any single engine block that was used by a manufacturer to produce *more than* ten different displacement engines? I have never come up with any.
Eleven, if you separate the two versions of the “265”. Twelve, if you count the “over-the-parts-counter-only “crate” “383”. Let’s name ’em.
1. 262 (3.671″ bore x 3.1″ stroke)
2. 265 (original) (3.750 x 3.00)
3. “265” (actual 263.1) L99 “baby LT1” of ’94–’96. (3.736 x 3)
4. 267 (3.5 x 3.48)
5. 283 (3.876 x 3.00)
6. 302 (4 x 3)
7. 305 (3.736 x 3.48)
8. 307 (3.876 x 3.25)
9. 327 (4 x 3.25)
10. 350 (4 x 3.48)
11. “383” (4 x 3.80)
12. 400 (4.125 x 3.75)
The original 265 was a step up from six-poppers; and showed the small-block potential, helped by use in relatively light vehicles. The ’94–’96 “265” was a de-stroked 305 existing only because of CAFE and cost-cutting. It was entirely inadequate to move the “Whale body” B-bodies that were it’s only application.
The 262 and 267 were emissions/CAFE/cost-cutting junk with no potential, no power, and without the expected fuel economy benefit due to being under-powered.
The pedestrian 283 and all the 307s were adequate…barely. 307s were never offered in a “tuned” version but the 283 was.
The 302 was never offered in a low-performance version, unlike the Ford 302 and the Pontiac 301. The 302s reputation was therefore never soiled by 2-barrel versions.
The 305 was another emissions/CAFE/cost-cutting piece of crap that existed only because (like the 267) it shared the stroke of the 350 crank so required no changing of the machine tooling for production. A 307–built with a better parts-bin selection of cylinder heads, intake and cam–would have been a far better engine.
The 327 and 350 were the real high-production workhorses; offered in two-barrel, four-barrel, and high-performance versions, and either could be had with fuel injection over the course of their production lives.
The 400 “coulda been a contender”; they were never offered with a four-barrel carb or “hot” camshaft (which they desperately needed) in cars, but some pickups got 4bbl 400 small-blocks. The 400 small-block should not be confused with the 402 big-block which sometimes came with “400” emblems on the fenders. Bore and stroke of the 400 and 402 engines were within a few thousandths of each other, but the engine character was vastly different.
Hindsight being 20/20, the 307, 327, 350, and 400 versions were the only ones Chevy (or enthusiasts) needed to bother with. The 302 was entertaining, but it was a homologation special, the 350 version was a better powerplant for actual use, gaining torque and losing little on the top-end.
The “crate engine” 383 was offered in versions for high-performance use, and also as an emissions-legal upgrade for ’96–’02 half-ton trucks. The only reason “383s” are popular in the aftermarket is due to the shortage of usable 400 blocks. The original aftermarket 383s involved a .030-overbore on a 4″ bore 350 block to clean-up worn bores, coupled to a reground 3.75″ stroke 400 crankshaft. When GM decided to get a piece of the aftermarket 383 popularity, they kept the 4″ bore, but added a bit of stroke to keep the “383” nomenclature.
An old gearhead once told me that putting a 283 crankshaft into a 327 engine netted a displacement of 301 inches, not 302 as GM said.
I have no idea if that’s a valid statement or not, but ‘302’ certainly sounds better from a marketing perspective.
301.6 cubic inches, which is closer to 302.
Not that 1cu in would really matter, but I think I’d go with Chevy engineers, not an “old gearhead”.
I’d give it a 50/50 split between the two for believability and hope there’s someone who has the ability to actually calculate it correctly for a definitive answer.
But that someone is not me.
An eight-cylinder engine with a bore of 4.00 inches and a stroke of 3.00 inches has an actual displacement of 301.6 cubic inches (or 4,942 cc). You can of course choose to round up or down (Pontiac did the latter with its later 301), but rounding up from 301.6 to 302 is hardly a scandalous obfuscation.
Thanks for the clarification. I can easily see hotrodders of the time considering it a 301 but GM (accurately) rounding up to 302. Regardless, as stated, it isn’t anything to get in a twist about.
Plus, Pontiac calling their engine a 301 to keep a distinction between the two divisions makes sense, as well.
Mathematically, 301.6 rounds to 302; anything 0.4- rounds down; anything 0.5+ rounds up. Which is why GM’s 301.6 CID “302” engine is truthful; Ford’s “5.0” (4,942 CC) is not, and GM’s 301.6 CID “301” engine is underpromising and overdelivering.
There is no hard rule here. Try pouring 1.4 quarts of a liquid into a 1 quart bottle! Rounding up or down and where one makes the break from one to the other is application specific. And marketing has no rules at all!
Completely different Euro mindset in the 60’s. Wheezy 900 CC four cylinder roaring at 4500 RPM to squeeze a liter of benzina for that additional kilometer or two. At the same time, handling the hair pin turns of the Alps with minimal effort.
North American mindset focused on the quarter mile and top speed with gas at 29¢ a gallon. With the evolving Interstate, not worried the least about handling or braking performance.
A few days ago, gas broke the $5.50 barrier in my neighborhood. A used Fiat 500 with a wheezy 1.4 liter engine is looking better each day!!
That’s a valid comparison.
But regarding the Fiat 500, have you ever driven one? I took a test drive just out of curiosity; I did not find it wheezy at all. With the manual transmission, the base 101hp engine felt brisk and I chirped the tires on a 1-2 shift…which rather surprised the salesperson who was riding along. The key here is light weight, once you start loading on cargo and extra people and the cabriolet roof performance is bound to decrease rapidly. But as a base model, the power to weight ratio is comparable to an old VW GTI. Once you step up to the Abarth turbo motor those Fiats are true pocket rockets. I would definitely consider one for a commuter car.
Poor me has to feed a thirsty ’92 Firebird with $10 gallon gas… remember me the next time you fill up your car.
The mission of this Z28 was quite different than the mission of the later plastic clad Camaros of the 80s
As a teen I didn’t like Camaros much becuase they were so common, but it’s nice to see a well kept original 60’s Camaro now.
I saw my first Z28 in ’67 I believe. I was in 6th grade. It was an SS, didn’t have the hidden headlights. Owned by a senior at the local high school. His dad owned the local Chevy dealership. Such a gorgeous car, dark green with white stripes. First rear spoiler I had ever encountered.
When I worked for Dennison Chevrolet in 2005 I actually saw one of these in the flesh. What struck me as odd was the giant smog pump attached to it.
I am not sure the 302 engine would be a good choice for daily driving. Drivers buy horsepower but they drive torque. A torque peak of over 4000 RPM is going to lead to a lot of shifting.
My ultimate Camaro of the era has a mid-tune 327, THM350, all the power assists and disk brakes, of course. I think it would feel plenty fast.
“Drivers buy horsepower but they drive torque.”
This is an old, tried-and-true auto industry adage. The other Trans-Am vehicle to which it applied was the Mustang Boss 302, as well. In fact, I actually once saw it listed as one of the worst cars ever built, simply due to the necessity of winding it out to the upper part of the RPM band for it to make the most horsepower. Other similar, high-strung, detuned race engines that went into production were the Street-Hemi and Boss 429.
One of the more recent examples was the Honda S2000 sports car. I once read a line that said the engine of that one “didn’t have enough low-end torque to pull the skin off a bowl of pudding”.
What I appreciate about these early Z/28s is they’re a fairly plain vessel for the homologation engine, save for the stripes, and ductail spoiler it’s really a very clean package, and the 67-68 RS on top of it is one of the few trim packages that actually makes the design less cluttered. Most people seem to put the 69 Camaros on a pedestal but not I, the cowl induction hood, fake louvers on the quarters, and the extremely fussy RS front end all turn me off with those, the 1970s were a return to form in my eye, eschewing once again visual clutter, but that evaporated again as the 70s progressed.
11mpg tells the tale of high RPM low displacement engines well, yeah they can make the power and get the timeslips of the bigger displacement engines but in a Camaro sized car they lug around town if you have an economy gear, so you’re always dumping fuel down the open secondaries, or you opt for a steeper gear like the 4.10s or higher to get some torque back but now it’s screaming along on the highway and top speed is cut way down, either way you’re not gaining much over a bigger engine, especially something like the 327 or 350 that won’t come with the front biased weight penalty of a big block. I greatly favor the idea of street homologation in Motorsport, as it makes both the sport itself and the production cars far more interesting, but that 302 rule seemed pretty silly considering they still were far from being true Trans Am race engines, the 70 Z/28, 71 Boss 351 and the T/A and AAR with their respective LT1 350, Boss 351 and 340 Six Packs are more appealing street engines than the previous 302s
Though there is something cool about the feel and aural sensations provided by high strung engines as they belt out the power while revving to the moon (I especially love the sound of a crossplane V8 in this role), but I couldn’t live with a rev-happy engine like this in day-to-day driving… or even in most performance driving conditions. Having to slip the clutch and nurse a peaky powerplant along in stop and go traffic gets old quick!
Most of the vehicles I’ve owned have had broad torque curves that plateau at low rpm, and very tall gearing… including the LT1 350 in my 4th gen Firebird. Yea, power tapered off at ~5500rpm and fell flat on its face at 6000, but it pulled hard from just above idle and was capable of mid-to-low 14’s. It hit 2000rpm at an indicated 83-84mph in top gear, and knocked down surprisingly good fuel economy.
I still wouldn’t turn down an opportunity to pilot an early Z-28, but am sure it woulda been pretty far down on my list of powertrain combos if I were alive in ’68 and looking for a Camaro for street use.
Mad Men featured one in an episode.
IIRC, Pete grew up in NYC, therefore, didn’t know how to drive.
However, in later episodes, he moved to the suburbs with Trudy, bought a Buick, and learned to drive.
I had a 68 Z/28 in high school. I could take the smog pump belt off and re-jet the 780 Holley and it would knock of nearly a second in the quarter. Stock they were jetted very lean. I won my class (Pure stock) at the 68 AHRA Summer Nationals.
Mine had 3:73 rears and I would go thru the quarter in 3rd gear at 100 mph, turning a14.38 time. It would do 70 in 1st, 90 in 2nd and 115-120 in 3rd at 7200 RPM. I had it at 6800 in 4th one time, but ran of of room to go higher. The RPM figures were with a Sun tach BTW, not a factory tach.