My Miller rockers needed to have the exhaust shafts changed every 30 to 40 passes. The offset load and narrow placement of the needle bearings caused the shafts to spall quickly. We were only running a flat tappet cam/double spring and turning the engine 7,000 RPM.
To solve the spalling problem, I replaced the needle bearings with bronze bushings. It helped. The shafts held up.
Miller outsmarted himself by adding the lightening hole in the exhaust rockers. I broke two or three rocker arms at the hole. After that, I had them shot peened to add a residual compressive stress to the underside and didn't break another one after that.
Miller was part con man. He didn't deliver some spare parts I paid for. I never saw the spares or the money. That was around 1989. He has resurfaced from time to time, but I wouldn't trust him if he actually had parts to sell.
OLD THREAD I KNOW, But needed some info added
We made new shafts for the millers, they were too soft, junk really, There were lots of issues with his BOSS ROCKERS, adding oil holes in the pushrods helped his adjusters live.
few weeks ago talked to WW,they still dont,and prob wont make any rockers for the stock heads
A441's,and the C9AE, AND D0AE BOSS heads rockers inter change, same holes, but the AR rockers need a little help in how they bolt down.
We have jesels under stock covers,It does take some grinding, but will clear.
If you maching the left side of the AR stand you can use both bolts to hold down the rocker
my jesels are about 30 years old on both of my current engines, switch out an adjuster,or bearing once in a while. great rocker
the stand holes have to be moved on the head to install jesels.
the jk heads have their own rockers ,with stands that are cast on the head, you cant shim these to get better valve train geo.
the C Carter heads once again take a different rocker,and dont interchange because of the stands with any head.
The TM head come with the normal layout,same as A441,D0AE,and the C9AE BOSS HEADS. and these also needs the holes moved to install jesels.
We have been working on BOSS ROCKERS,and hope to have something soon for show and tell.