It's the ultimate LS-engine "what if" scenario: Could the blower from the Corvette ZR1's LS9 engine be dropped on the larger-displacement LS7 found in the Z06? That would create the ultimate "factory" combination—especially because it would drop into any GM truck that came with an LS engine, dating back to '99.

Enthusiasts started dreaming up this ultimate power combination the second the LS9 was revealed to displace 6.2 liters, rather than the LS7's 7.0L size. That's a significant 13-percent difference in volume, but GM said it went with the smaller bores to ensure a safe, long-lasting powertrain—one that would be subjected to considerable boost pressure over its lifetime.

"On the OE side, all the considerations for 100,000 miles worth of durability must be considered," says an anonymous GM drivetrain engineer we spoke with. "The power goals for the LS9 were reached with the smaller displacement, which offers thicker cylinder walls for greater safety margin, so there was no need to step up to the 7.0L displacement."

That's a great textbook answer and we certainly wouldn't cast aspersions on the LS9's 638 hp output, but when there's a larger-cube version of the same engine family, you just know the performance world wouldn't let the combination go untried. That would be like Dr. Frankenstein having both a spare brain and access to a graveyard, but passing on the opportunity.

Brian Thomson isn't Dr. Frankenstein, but he's created more than his share of LS-based monster engines at his shop, Thomson Automotive near Detroit. In fact, he's had great success melding the LS7 with the LS9 blower, developing basically a crate engine package (including a pre-programmed E67 controller) that delivers around 770 hp and 840 lb-ft of torque on pump gas. The torque comes on soon, too, making more than 800 lb-ft by only 3000 rpm, which really helps launch today's heavy GM trucks.

"It's a sweetheart of a street engine," says Thomson. "It starts, idles, and has the low-speed drivability of a stock engine, but when you tap into it, it's amazing. With more than 800 lb-ft and the instant power delivery of the blower, it's an engine with two distinct personalities."

OK, so maybe it's not Frankenstein's monster, but more of a Jekyll and Hyde engine. Regardless, we recently took note of the assembly and dyno-testing of one of these engines, which was destined for the Chevy S-10 project vehicle of New Yorker Joe Jones. It officially made 769 hp and 844 lb-ft, with a safe air/fuel ratio of about 11.4:1 under full boost.