Chevy’s 302 Small Block Engine Was Meant to Break the Rules – Jalopnik

The Camaro, rest in peace (for now), was usually given the hand of the Corvette, if it had anything unique at all. There were no production Camaros powered by the C4 Corvette ZR-1’s dual overhead camshaft LT5. Corvettes had standard four-wheel disc brakes since 1965, but were optional on Camaros until 1993. The L98 Camaros of the 1980s and 1990s only came with automatics, while the L98 Corvettes had optional manuals. The C4 Corvette LT-1s made 300 hp, while the 1993-1997 Camaros made it with 275 hp.

However, there was one item that Camaros could brag about that Corvettes never had. No, not the back seat, we’re talking about the high-revving 302 V8 in the Z28. (It was also in the Z/28. And, if articles and books of the time are to be believed, the Z-28.) To get the Camaro ready for racing, Chevrolet installed a forged 283 crankshaft in a small 327 block, creating a 302.4 cubic-inch V8 that fit nicely into the rules of the Sports Car Club of America (SCCA) Trans-AM racing series.

So, how did the Chevy 302 “break the rules?” Well, it wasn’t SCCA rules that ruined the engine, it was muscle car rules. American V8 engines made power through sheer displacement, dangit! Forced induction was found on ’57 Fords and Oldsmobile Jetfires, yes, but they were outliers. And sure enough, Corvette 283s and 327s were fuel injected from 1957 through 1965, but the American sports car couldn’t resist the call of cubic inches for long, with the ’65s getting an optional 396 that became a 427 the following year. Speaking of fantastic plastic, that’s the other rule the 302 broke: Corvettes have never had one of the coolest engines! I couldn’t even find evidence of the production order (COPO) 302 Corvettes from central office.

In 1966, racing at Chevy was still verboten thanks to General Motors’ 1963 edict that immediately shut down factory-backed competition. But the lure of “win on Sunday, sell on Monday” was irresistible, especially as Ford and Chrysler ate up the Trans-Am publicity. GM saw dollar signs and management liked dollars, so the racing was back on for ’67.

The 1967 Z28s were not a separate version, but rather an RPO code that prepared Camaros for Trans-Am racing. Z28s received the 302, heavy-duty engine cooling hardware, stiffer suspension, front disc brakes and deep groove V-belt pulleys. Additionally, the only transmission was a manual (as God intended) and it was the close-ratio M21 non-rock crusher Muncie four-speed. Perhaps the coolest visual feature in the interior was an optional tachometer that read 8,000 rpm.

The 302’s four-inch bore and three-inch stroke were a recipe for high-end power that thrives on racetracks. Engines with a bore larger than a stroke are called “oversquare”. Other monster engines of the era were also oversquare, such as the LS6 454, 426 Hemi and the 427 FE; but the 302 was overly square in comparison, and F1 fans knew that more oversquare meant faster turning.

Few engines can hit around 7,000 rpm as that Chevy 302. If you were to buy a Ferrari 330 GTC to get a screaming V12, it would also max out at around 7,000 rpm. Even the Corvette’s LT-1 350 only revved around 6,500 rpm, though its increased horsepower was attractive enough for Car and Driver to commit heresy in 1969 and put one in a Z/28 Camaro, which it called the Blue Maxi. A shame. The 302 may not have low-end torque, but it certainly screams from the top of its carburetor jets.

For 1968, the Z28 was a real version until 1969, styled as “Z/28”. Magazines and books, like the May 1968 Hot Rod issue I’m holding in my hands now or the American Muscle Cars book (with a rare cross ram, for example, a JL8 four-wheel disc brake), printed “Z-28”. Second generation Camaro Z28s got LT-1 350s and lost the slash.

The 302 received steady updates throughout its three-year lifespan. The first year 1967 302s had small 2.30-inch main magazines, while the ’68s got stronger, larger 2.45-inch magazines. The 1968 blocks also produced a net with four bolts in the middle three positions. For 1969, the standard Holley four-cylinder dropped from 800 cfm to 780 cfm, although the optional cross ram used two 585 cfm Holleys. Early ’69 cars also had the NC8 chambered exhaust system as standard. These chambered pipes can shatter windows, but let that Chevy 302 sing.

Meanwhile, the Camaro’s sibling, Pontiac’s Trans Am, couldn’t simply put cranks and blocks together for the right displacement. To have a shot at racing in the car’s namesake series, Pontiac created a custom 303 cubic inch engine with Ram Air V heads. The heads had intake runners sized to flow about 325 cfm, but the relatively small engine couldn’t utilize all the potential airflow. Although testing with modified Ram Air IV heads was promising, Pontiac’s 303 died on the vine, while Chevy’s 302 made good wine. All 1969 Trans Ams are rare, but Trans Ams with 303 engines (less than 25) are rarer than death by automatic (about 37 per year).

The 302 Z/28s were short-lived, but led Chevrolet to numerous Trans-Am victories in 1968 and 1969. That high-twist little engine spun like a centrifuge, never graced Corvette engine bays and broke muscle car rules. And that rules.