I am running DOOE heads on a 302.. 7/16 studs, springs 140/150 seat about 450/460 open. Using Crane Cobra rockers. Dont think these are realy sturdy enough. Max RPM of engine is somewere over 7200 RPM. Havet pused that envelop as a few componets in the engine hold me back. Factory hyd roller lifters and the rocker arms. Will the Millers handle it?
I am not sure what you mean by "Crane Cobra rockers," (do you mean the factory 1.7s?) but to generally answer your question these Miller rockers are easily capable of handling your noted spring pressures and noted 7200 rpm at least as well as (and likely better than) most brands available for the SBF. We have customers using them in big roller-springed drag racing engines, in big roller-springed road racing engines, etc, and subjecting them to higher rpms (along with a rocker stud girdle) than your noted 7200.
They are made of 7075 grade aluminum and have a destruct level of about 83,000 psi at 250*F. Compare that to SBF Crane gold which are made of 6061 and I understand to be closer to 63,000 psi (which is also very good), and Scorpion which I believe has a destruct level of almost half
that of the Crane rockers (~33000 psi
I think that these Miller rockers are among the top of the line SBF stud rocker arms available, from a materials stand point (both the aluminum and the steel), from a geometrical engineering stand point, from a performance stand point, and so on. Same source of high quality needle roller bearings as used by Jesel, T&D, etc. As noted at the top of this listing, they can accomodate a big 1.625" roller spring. Further, the rocker slot is designed to accommodate at least 0.800" lift at the valve (assuming Mid-Lift geometry setup--other methods will lessen that ability on pretty much any brand stud rocker).
Please call, email, or PM directly with any further questions.