Old vs. New: Engine

For me this is a no brainer. You certainly can save significant money going with a donor engine (e.g. LS1, LS6). The GTM achieved the its extreme performance numbers with a LS7 hooked to a Porsche G50 transmission, and 0 - 60 in 3.0 seconds flat is something everyone should sit up and take notice. If we take the nominal GTM curb weight of 2400, then the power-to-weight ratio for the demo car 0.210416 HP/lbs.

The curb weight for Corvette Z06 is 3180 pounds. The LS7 is the base engine for the Z06 and this has a p-t-w ratio of 0.158805 HP/lbs.

My 2003 C5 (as currently configured) has a curb weight 3214 pounds. It has a modified LS1 engine and it has a p-t-w ration of 0.124455 HP/lbs.

The base LS3 engine produces 430 HP. In a GTM, the p-t-w ratio is 0.17916 HP/lbs. This is already higher than the Z06, which has a published top end speed of 198 mph.

For emission conscious locales. GM provides green E-Rod engine with the same p-t-w ratio. I only include this engine for completeness. It is not on the list for engines in my GTM.

For close to the same money as the base LS3, there is a more powerful version called the LS376 engine that produces 480 HP. In a GTM, the p-t-w ratio is 0.2 HP/lbs. This engine set up approaches the powerful LS7 used for the demo car. Now we're talking! The MSRP is $8,075. If you shop around, this engine can be found for as little as $6,100.

Granted horsepower isn't everything, but it is the heart of the beast.