80/20 Rule

No idea what the 516's flow, but I'd be surprised if they make 250 cfm.
For the Speedmasters, here are the numbers from Dwayne.

OOTB:
Lift——-in/ex
.100— 67.5/53.5
.200—137.2/101.2
.300—202.8/138.3
.400—241.2/160.3
.500—256.1/171.2
.550—262.5/174.4
.600—269.2/176.9
.650—269.2/178.1
.700—269.2/179.3

After:
Lift—— in/ex
.100—- 72.5/62.7
.200— 148.8/105.4
.300— 217.6/143.9
.400— 261.8/171.5
.500— 286.1/190.5
.550— 290.5/197.8
.600— 292.4/203.7
.650— 293.5/208.6
.700— 294.3/212.2

Probably more suited to a slightly smaller cam, but I always wanted to run a Mini-Express mushroom setup :)