Once again, the big news from...
Once again, the big news from General Motors revolves around theCorvette, this time centering on the introduction of the race-derived427-cube LS7 powerplant that motivates the new '06 Z06. With a rated 500hp at 6,200 rpm and a 7,000 rpm redline, it's an engine that's sure toplease.
From an engine builder's perspective, looking at new OE engine designsalmost always leaves us with a trace of self satisfaction and maybe ahint of smugness. Looking over a newly introduced factory powerplant, wemay say, "That's a nice piece." Inside, however, the hot-rodder thatlives in our consciousness leaves us with a pleasant thought: Nice for astocker, but I can make it better.
Qualified that way, we feel an air ofhaughtiness, real or imagined, while reveling in what the OE left on thetable for us to exploit. Some porting in the heads, a little morecompression, trick rings and bore finishes, lightweight parts, and soon; our hot-rodder's bag of tricks runs deep. Unconstrained by theimpositions faced by mass production, our custom efforts allow us thefancy of outdoing monolithic corporations wielding unimaginableresources. Normally, this ego self-gratification is part and parcel ofany OE engine review. Then it happened: the LS7 small-block debut. Theonly reactions for someone truly in the know are deference and awe.
The fantastic cylinder heads...
The fantastic cylinder heads define the engine and are key to its powerproduction. Reportedly achieving airflow in the realm of serious racepieces, the ports are substantially revised.
Thesize alone gives it credence: 427 cubic inches in its all-aluminumsplendor. Matching the displacement (coincidentally?) made famous by themost legendary of performance Corvettes from a generation long past,this is the largest "small-block" engine ever produced by GeneralMotors, while maintaining the external dimensions of previous Gen IVsmall-blocks. But it encompasses so much more than its internal girth.With a rated output of 500 SAE net horsepower at 6,200 rpm, the realmechanical energy emanating from this beast far outstrips any of thebig-blocks of yore.
Based on the groundbreaking Gen IV small-blockarchitecture introduced as the LS1 in 1997, the LS7 is much more thansimply a displacement increase. It's an exotic 7,000-rpm race-derivedpowerplant brought upon the public at a level of execution unrivaled inany production car. Dave Muscaro, assistant chief engineer for passengercar V-8s, put it succinctly, "In many ways, the LS7 is a racing enginein a street car. We've taken much of what we've learned over the yearsfrom the 7-liter C5-R racing program and instilled it here. The realityis, there has been nothing like it offered in a GM production vehicle."