It is really a very simple concept. You want to move a truck, which is work. You want to do the work quickly. Work done in time is power. So to do the most work, in the least time, you need the most power.

Since an engine is a transient device, peak power is meaningless. Imagine a case where you had a 700 hp peak, but 200 rpms on either side of it it was down to 300 (wouldn't really happen, but consider the case since the math still works). That would be worse than an engine that made 500 hp over the entire rev range (also couldn't happen, but the the argument is good).

Also consider that the engine, in general, while drag racing is only operating in a small rpm band. That band is the only area of interest. So for the fastest truck, you want the most average power in that rpm band.

Note that this ingores the launch, where the power at the launch rpm is critical.

 

etc. etc. etc.

 

4:10 gears, shifting at 6000 rpm (power peak at 5400-5500 rpm) trapping 115 mph at 5400 w/30" or 5700 rpm w/28" with ported eaton, motor hits 6500 rev limiter fairly regularly. This is about the limit with my current valve train.

Shifting at 5000 - 5200 rpm increased ET by ~0.3 in 1/8mile and ~0.5 in the 1/4.