Few things. Data log mixtures at full throttle and part throttle, do the same with ignition timing. Also, velocity equals torque, 75% could be helping you make more lol

Air velocity and torque:
Air velocity and volume flow
Air velocity is the rate at which air or gas moves in a specific location, usually measured in feet per minute (FPM). You can calculate the volume of air flowing past a point in a duct by multiplying the air velocity by the duct's cross-sectional area, which is usually measured in cubic feet per minute (CFM).
Air velocity and torque in engines
For good throttle response and torque, street cruising engines need high air velocity below 4,000 rpm. Smaller intake runners and valves can help achieve this higher velocity.
Air charge and torque
The air charge into an engine's cylinders is a function of the engine speed and the mass air flow rate into the cylinders, and it's directly related to the torque produced during the power stroke.

I love the assumptions before making any measurements.

"Drives better" how - did you make acceleration measurements?
Did you put the car on a dyno and actually measure the torque curve?

Until that's done, any further discussion is a complete waste of time.

log don't guess. this thread is pointless w/o data