“The LS7 block will easily accommodate a 4.125-inch stroke, but you really don’t want the stroke larger than the bore,” says Thomson. “That undersquare condition increases piston speed, increases friction, and generally puts more wear on the reciprocating assembly.

“If we were building a big-torque, low-rpm truck engine, then an undersquare combination might be acceptable, but we’re building an engine that we want to rev high and make big horsepower, so there’s a practical limit to increasing the stroke.”

Journalistic instincts prompted us to explore all sides of the story, so we pondered potential alternatives to this naturally aspirated powerhouse. For about $8,200, Edelbrock’s E-Force supercharger kit for the LS7 is rated at 657 hp and 582 lb-ft of torque, or about 88 percent of the power and 91 percent of the twist for about 70 percent less money (not including installation). That’s a significant price difference, but again, the performance profile of a naturally aspirated engine is much different than that of a forced-induction one. Determining which approach is preferable for you really comes down to the manner in which you intend to use the car.

We’ve sampled the Hurricane 442 in Thomson’s personal ’11 Grand Sport and can attest to its performance. The low-end torque is explosive, and the high-rpm power surge seems to have no limit. The engine just keeps pulling until you run out of nerve, road, or both. Low-speed and part-throttle driveability is excellent, too.

Cost, however, is definitely a factor. If you’re simply looking for a faster weekend cruiser and occasional dragstrip warrior, a bolt-on blower kit probably makes more sense. On the other hand, if your plans include exploring the boundaries of your Corvette’s performance on a road course or deserted highway—and your checkbook can swallow it—this is one of the best naturally aspirated LS7 combinations we’ve ever encountered. Quite simply, it rocks. vette


Engine-Dyno Test Results
(STP Correction)

Rpm Lb-Ft Hp
3,000 447 255
3,100 457 270
3,200 469 285
3,300 501 315
3,400 502 325
3,500 497 331
3,600 483 331
3,700 478 336
3,800 484 350
3,900 496 368
4,000 507 386
4,100 525 410
4,200 559 447
4,300 598 490
4,400 617 517
4,500 610 522
4,600 595 521
4,700 594 531
4,800 597 546
4,900 606 566
5,000 619 589
5,100 624 605
5,200 641 635
5,300 648 654
5,400 652 670
5,500 651 682
5,600 640 682
5,700 633 687
5,800 625 690
5,900 623 700
6,000 606 693
6,100 610 708
6,200 612 722
6,300 596 715
6,400 595 725
6,500 598 740
6,600 584 733
6,700 574 732
6,800 558 723
6,900 553 726
Peak numbers in bold

SOURCE
Thomson Automotive
Wixom
MI
248-349-0044
www.thomsonengines.com