Broken rocker stud. wrong length pushrods?

[rdc767]

The flat side of the roller rocker tunion was up for the poly lock. I can see how this could happen.

The arp studs are longer 1.75 compared to 1.5 for the stock... With shorter pushrods should bring the rocker lower on the stud.

I did wear check with a felt marker on a few location and it looked ok..... Next will be stock legnth.

Most of the wear marks are centered. But some are on the sides. Just from researching Pro comp heads on different forums there are reports that the pushrod guides are off and the studs are off centered too.(cheap machining in china) Looking at the guides you can see it. Isky make a adjustable guides I will try. The rockers look in good shape with no stress marks.

thanks again for the thoughts.
Ron

[Rick Parker]

Ron: The Isky adjustable guide plates are a very good and often overlooked idea. They can be carefully tack welded (Tig) after final adjustment and alignment is achieved to eliminate future movement.
Take your time to get the roller directly centered over the valve stem. Recheck after tightening the stud on the guide plates.
Don't be so quick to denigrate the heads you have. They are marketed at a very attractive price point. Yes they may need to be "touched up" but just treat them as castings and add good hardware, pay attention to details and you'll have a very good set. Many that aren't aware of it, have their pushrods and rocker tips misaligned on 289, 302, & 351's. It is very common. That was the purpose of the shaft mounted rockers being developed along with eliminating the side to side flex in the stud as the valve opening forces are exerted upon it. Cycle the engine and look at the areas where the pushrod gets close to the head itself in the slot. Be certain they do not "bottom out" in the slot (doubt they will) unless you are using a high ratio rocker arm (1.7+). Also keep an eye on the area where the spring is under the rocker arm close to the stud sometimes the rocker will hit on the spring retainer.

You're on the right track....just keep an eye on all the details.