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1175 HP

This engine, and others like it, has opened up a brand-new chapter in the ever-evolving, wild world of Chevrolet power. By design it has a bore and stroke of 4.60 inches by 4.25 inches and Big Chief II heads, which are about 2 inches taller, that feature oval-shaped intake ports. This, they say, is for maximum cylinder filling. Years ago, creative racers would angle-mill heads to arrive at the desired combustion chamber size and to improve the valve angle in combination with the incoming intake flow. These heads are nicknamed “11-degree” heads, as they have been designed with a built-in 11-degree angle right out of the box. There’s no angle milling needed here. A special valvetrain is necessary, along with longer stem valves. Quarter Mile Performance feels that these heads are worth 200 additional horsepower over the very best “shorter” heads.

SO CLOSE!

We saw extreme boost levels in our quest for horsepower from the little supercharged V-6 with out ’94 Supercoupe. With the Magnum Powers MPx supercharger clearly capable of more airflow than we could support (boost climbing north of 23 psi), it made sense to work on the heads-and-cam combination to better deal with some of that boost.

REDEEMING THE FORGOTTEN Y-BLOCK

When Ford introduced its Y-block engine in 1954, it labeled the engine the worthy successor to the venerable Flathead. The Flathead gained a loyal following of hot rodders and racers, but the big Cadillac overhead-valve V-8 and Oldsmobile’s Rocket 88 were stealing Ford’s thunder in terms of power, so something had to be done, and Ford decided to respond. The answer was a clean-sheet V-8 design, featuring overhead valves and improved cooling compared to the old Flathead. It was dubbed the “Y-block” because of the way it looked and because of its deep skirt and tall cylinder heads.

ON BORROWED TIME

When you go looking to make huge power from your 5.0-liter Ford, the limiting factor will always be the weakest link in the chain. In the case of our supercharged 331 stroker buildup, the weakest link turned out to be the production block. Like most enthusiasts, we had no budget for a DART racing block or even a Ford Racing Sportsman block, but we decided to tempt fate nonetheless and go for a big power number on the dyno. Considering that the stock fuel-injected 5.0-liter was rated at a measly 225 hp, even a 300hp buildup would offer a welcome change in performance.

539HP 383 On Pump Gas

Time and time again, our advice to those interested in learning about stout-running engines is that it’s the total combination that makes it all happen—considering, of course, that components are prepped, cleaned and assembled as if in a “clean room.” 

High Performance Rebuild

The small-block Chevy has enjoyed a long, happy life. Sure, the current LS1/LS6 version is quite far removed from the original, but thousands upon thousands of little mouse motors continue to provide the sole means of motivation to everything from stationary irrigation pumps to Le Mans-winning C5R Corvettes. Naturally, this list also includes all manner of boulevard bruisers, street stompers and resto rockets. Heck, we’ve even seen little Chevys under the hood of “Brand X” machinery. The continued popularity of the small-block Chevy is not surprising. Take a look at the combination of power potential and parts availability and multiply that by the cost quotient, and you have the makings of a real success story. Add to this equation the millions of project motors just sitting around  junkyards throughout the world, and it is easy to see why enthusiasts continue to embrace the mighty mouse motor as the performance powerplant of choice.   

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.  

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.

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