Honestly...how good was the 318...mpg / durability / hp

I'm on my 9th 318 powered Mopar.

My first was a '66 poly that never lost a street race to a gm product in two summers of being a 16/17 year old kid.
Bone stock 2 barrel, 727, single exhaust, 2.94 open...but carefully tuned with some low and zero buck tricks.