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Engine

’65-’66 MARK IV

The birth of the Mark IV 396 for public consumption occurred back in 1965. Its predecessor, the Mark I, started in 1961 on the drawing board, was finalized and built in late 1962, and was unveiled in race trim in 1963. It set the racing world on its collective ear at Daytona and other races, and then it disappeared, going back to Chevrolet Engineering for further development. Seeing that you could step up and possibly own the Marilyn Monroe of big-block engines, serious racers and enthusiasts had to sit on their hands for two full model years (1963 and 1964) before the son of this absolute powerhouse could be ordered. 

VINTAGE ENGINE REBUILDING

Thirty-five years and $636 ago, we bought an 80,000-mile ’62 fuel-injected Corvette in Fresno, California. Sadly, the car had been stolen once. The fuel injection was gone as well as the T-10 four-speed transmission. A pair of bare 461-X heads was in the trunk. The engine was found to have a rocking rear cam bearing, which caused oil to shut off to the rocker arms at high rpm. At the time, the prognosis was that it could not be fixed, so the motor was replaced with a ’68 350hp 327. Since 1976, the car has been in storage, along with the original engine.  

Pump It Up

Small-block water pumps are common replacement parts and are available at prices that are nearly impossible to beat. However, while getting a brand-new water pump for cheap is great, sometimes you need to keep the one you have. If it’s date-coded, or maybe you’ve installed a chrome steel or an aluminum water pump. You aren’t going to get those at the parts counter. In cases like these, rebuilding a water pump is preferred to buying a new one. 

Shade-Tree 1.6.

Okay, we weren’t quite that naive about what we read regarding upgrading to 1.6 rockers on our small-block Chevy for the first time, but it was close. 

The engine in question was a decent runner with 30,000 miles on the mild-performance rebuild. The rebuilt engine was purchased used, and among its selling points were 0.030-over 9.5:1 pistons, moly rings, 1.5 roller rockers, a Performer RPM intake and a brand-new Holley 750cfm carburetor. The cam wasn’t a perfect match to the torque converter used in the previous installation nor was the final-drive gear ratio. As a result, the owner planned on stepping down on the cam chart to a Comp 286H-10 cam, which came with the engine in its original box. Also included were a brand-new factory Z28 oil pan and a factory timing chain cover to replace the cheap chrome pieces. For $300, the engine package was a deal, and one we couldn’t pass up. We sold the aforementioned chrome pieces and matching valve covers for $50, getting us the engine at the bargain price of $250, and we still had the new cam and lifters on our shelf.

Choosing The Right Cam

Cam-speak is a language all its own. Well, maybe not from a linguistic point of view, but it is a specialized dialect of car-guy talk. Although spoken by a good portion of enthusiasts, Cam-speak is really fully understood by only a handful of those same enthusiasts, as it is a very specialized, nuanced dialect.

A Bit of History

Hundreds of thousands of these “little” big-blocks were sold in the 1960s. In 1965-66 alone, over 150,000 came in the Impala, Biscayne and Bel Air big cars. Few paid attention to them because the hot engine of the day was the L-78 with high-rpm, rectangle-port heads. But when stock eliminator drag racers began flogging the L-35, it responded magnificently.

CARB OR EFI?

What makes more power: carburetors or computers? While the ultimate answer is that a sophisticated electronic fuel-injection system will virtually always outpower a carburetor, the real question may be whether the power gains are worth the extra expense and complexity of installing an EFI system.

COAST-TO-COAST 482ci STREET 409

You can drive this bad boy coast to coast and burn all the rubber you want in between.” That was Day Automotive’s Tony Shaffer proclaiming the abilities of his shop’s 482/409. Soon thereafter, we were entering the confines of Day Automotive in Independence, Missouri, where Shaffer and crew had just completed the engine in seven days. It represents what can be accomplished power-wise with the right combination of parts, plus some internal modifications. And with a 10.0:1-compression ratio, it’s very street-friendly.  

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