Anyone using the big block Comp Cam Pro Magnum rocker arms with a hyd roller cam? Their website about the pro mags has a statement that the arms are recommended for 350 open lbs of spring pressure or less. I would think a hyd roller cam around .560 lift would go beyond the open pressure of 350lbs. Strength of the arms should not be an issue since they are made of chromemoly steel.

Also have they changed the design of the rockers (#1321-16). The old rockers had a teapot curved arm design where the roller is located. Now the website picture has a more straight roller arm design and a more open area in the bridge location.

Yep, I've used them a bunch of times with hyd roller cams. I haven't tried the new rocker arms with the bushings. I'd like to get a set of those to see how they work.

I think you would be fine with any spring for a hyd roller cam. A beehive spring would be my choice for any hyd roller setup. If the spring is super stout then just hone the rocker arms for another 0.001 of clearance and you should be fine.

It's interesting you say that the recommended spring pressure is 350 lbs. If you look at the recommended spring on the Comp Cams website where the matching parts are shown, it shows open pressures of 450 lbs. I am using these rockers with their XR274R Street Solid Roller with 500 lbs. open and have not had any issues for at least 4 years now. However, I did banana groove the shafts for better oil distribution.

AndyF, is Comp putting bushings in the pro magnum rockers now?