It's torque at the rear wheels, not torque at the crankshaft, that determines acceleration and it's horsepower that determines how much RPM you can trade for wheel torque. The more horsepower you have, the more RPM you can trade for torque at the rear wheels via gearing. I derived the relationship from fundamental concepts and did a write-up several years ago:
http://www.mustangsandmore.com/ubb/D...orqueVsHP.html
Dan Jones