We think the Millers are the best SBF stud rocker arm out there for the money and among the best stud rockers for the SBF at any price. None of the other rockers offered at this price come with comparable materials, composition or technology behind them, nor will you find any other roller rocker with a rocker body made of 7075-T7 aircraft aluminum, with anywhere near the fatigue / destruct / tensile strength capabilities, and the 8620 billet steel trunnion, all at our comparable pricing.
Don't put your high performance engine build at risk with el cheapo rocker arms, buy quality!
We have these rockers available for 7/16" and 3/8" stud applications. However most people with heads like yours remove the press-fit studs and tap the hole for the 7/16-14 coarse thread (the stud hole in the head is the correct size for the 7/16 tap). I don't recommend using the OEM press fit studs in a high performance application. It's also possible that the OEM studs will be too short for roller rockers, but that scenario depends on the overall valve train setup and the actual rocker arms being used (parts combination).
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.
For how long? We cannot garantee that the price won't go up in the future as they are significantly discounted. I just can't say for how long we can maintain the current pricing.
Well I'm not sure. May be 2-3 years before I put my small block together. Try not to jump the gun on parts too much, just in case plans change, but the deal is good.
On those cylinder heads, most aftermarket rocker arms have a clearance issue at their trunnions due to the valve placement, meaning that the trunnions to the adjacent rocker arms touch each other. With those aftermarket rocker arms, the simple fix is to grind the trunnions down for clearance--welcome to the world of custom engine building. I do not know whether the Miller rockers need clearancing or not...but if they need to be clearanced then simply clearance them as you would all the other brands.
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