ya my 'sweet spot' query was more along the lines of 'where is the optimum rpm range for a 318 for maintaining speed', not for max power. More like, where in the rpm band is 'good/enough' torque generated.

I really wish there were dyno results generated where the engine isn't at full throttle, IOW a half-throttle dyno run showing how much power is generated in a 'normal' driving condition verse WOT. WOT isn't what I'm concerned with - I want to see the power levels for an engine in the rpm range where it spends all its life.

Thanks for the reply. If 1800 rpm is an efficient/maintain speed rpm for a mag 318 then I'll be happy to leave the gears alone. Conveniently, 1800 rpm is also the sweet spot for a 4bt Cummins....