What is an estimation of horsepower and torque on a chevy 502 crate motor with headers and two 780 holley carbs?? What is the maximum rpm the engine can run with these modifications?? What is an estimate on top speed with 7.18 gears and 48 x 31 tires?? I'm building an off road machine. What is more important for off roading, horsepower or torque??