What is the difference between betwen the two? 20+ HP? Does anyone know the internal differece? Just wondering. I'm sure I'm not the only one.

 

 

????!!!!!!!!!!

 

The LS3 is the same design used in the Corvette and is rated ay 426 HP with the manual transmission and the L99 used in the Automatics I believe is the 6.2 L truck engine using the 4-8 displacement on demand design and is rated at 400 HP.

 

What would be the main reason for going with a slightly different power plant under the hood? HP is reduced a bit, power management for fuel savings, HP vs torque curves similar? Their must be a reason for doing a LS3 manual trans vs a L99 auto trans technical reason behind the change....?

 

Check this link to Super chevy .com They go into detail about the differences between the engines.

http://www.superchevy.com/features/c...ons/index.html

 

My guess would be the auto without the 4-8 management would not meet the fuel standard and would be subject to the gas guzzler(?) tax. The Corvettes only weigh 3200 lbs and therefore didn't have that problem.