cam duration question for 416.

I have one with a hydarulic Crane H302-2 that idles clean at 800 and gets 17mpg... That cams 238° @ .050 intake, 248° @ .050 exhaust. It also pushes 3800lbs to 12.80s @ 109mph with 3.23s on pump fuel.
One I just delivered has a hydraulic roller, 248° @ .050 intake, 252° @ .050 exh, and that one would idle fairly well at 700 with no load (running stand). The 2nd one is more compression and RPM heads but similar carb/intakes.
A very nice idle will be there with most cams around 240° but the power will be peaky and more torque than horsepower. If you want to make decent power with an idle around 850-900, go 250° @ .050 and you'll bring the horsepower up without losing torque, but the torque curve will be less flat.