LS1's will and can do almost 13's flat with no mods. lt1= more low end torque, and ls1 has more top end power and is better for drag racing.
General Specifications
Displacement 5.7L (5665cc, 346ci) Gross Horsepower 310 @ 5200 RPM, 320 @ 5800 RPM
Bore/Stroke 3.90/3.62 Gross Torque...