An engine will always accelerate fastest at the torque peak in any given gear. Horsepower comes into play when you factor in gearing. Lets say you have engine a and engine b. They are similar but engine a makes 200lb-ft of torque at 2000 rpm and then suddenly drops off and engine b makes 200bl-ft up to 4000 rpm. So, engine b makes twice the hp of engine a because hp = torque/rpm. They are put in the same car with the same gearing. They will both accelerate off the line the exact same, until engine a has to shift because it got to 2000rpm. Engine b will pull ahead because it can continue to accelerate in 1st until it reaches 4000, and the car with engine a will be behind because it is in 2nd. Kapiche?
So really, since we can change the ratios in the lfs cars, to achieve the highest top speed it's all about hp.
Edit: another thing to think about. You can run a twice as short gear ratio in the car with engine b and reach the same speeds as engine a, ( since b can reach twice the rpms) but since engine b's ratio's are so short it will accelerate almost twice as well because torque to the wheels is twice as much.
A Lotus Elise/Exige type car. A big v8 musclecar, a modern american v8 car like the Z06 corvette/Dodge Viper (Yes I know its a v10). Hey american cars aren't bad guys, the Z06 is the second fastest production car to lap the ring.
I went into the FM Oval server twice and got booted right away for no apparant reason, the third time i got the "Host Refused Connection" message, but it's ok now. All is not lost!
I think real tracks would be awesome, too. But how many people have heard of limerock before? Especially other than those that live in the northeastern US.