It's amazing how few people can grasp the concept that tuning an engine for 5000rpm doesn't work so well when you only spin it at 2500rpm. Few believe how long and skinny the optimum 2500rpm intake runners are.I have be preaching for a long time about using single port heads for under a 2180 cc engine and 1 1/4" dia intakes tubes instead of the 1 1/2" tubes for a higher velocity intake charge for more low rpm torque for a straight drive engine. Yes, efficient flow over max flow for prop RPM's. Side benefit of no head cracks between the spark plug threads and valve seats.
"But the hotroders do this " is in peoples thinking.
Also the hot oil box was a big improvement in power and smoothness plus lowered the oil temp 20 degrees.
My 1835 cc engine is a torque engine and when at the end of the runway and start adding power, you feel it.