I have a 622 ci RB with B1MC heads (with 1.7 ratio T & D rockers). The Crane solid roller cam now in it has .850" valve lift, duration @ .050" in/ex is 286/306. The owner wants to replace this cam (because of too many clearance issues) with a cam that will yield approx. .800" lift with the 1.7 ratio rockers. This engine will not see more that 7200-7400 RPM's.
I'm looking at two cams, 1st is a Lunati, duration in/ex @ .050" 282/290 and .806/.806 lift, 2nd Comp Cams, duration @ .050" in/ex 285/292, lift .800/.800
With this size engine, how much duration would be best with .800" lift? We really would rather stay with a "off the shelf" cam, not a custom.
Or is there another choice that I'm not seeing?

Thanks, Brian

I only run a 528 with 440-1 heads, and it has gone fastest with a tight lash, inverted flank cam from Mike Jones, with .870 intake lift and if i recall corectly almost as much on the exhaust. The duration specs are 285-296 on a 114lsa in at 110. Lift at the point of possible interferance is what you need to know, not so much total lift. Lobe seperation and net lift after lash at the critical points is what counts.
My guess is you need all the duration you can put into it up to, or close to your old cam.
Figuring your heads probably flow 460 cfm, your motor has about the same flow per cubic inch as mine, but it is almost 20 percent bigger, for what all that is worth. I am sure. alot more needs to be taken into consideration to steer you right.