Sorry to jump in but......here is what I have found: I run a 441 LS7 and have run large cams using the crower shaft rockers (stainless). In an effort to reduce weight and get a couple hundred more stable rpm out of it, I swapped to the H/Sharp modded stockers. Broken intake rocker bolt at 95mi. Replaced. Broken intake rocker (different) some 50-60mi later. The crowers are back on as this is my daily.....

 

Yes the bolts are the problem the 8mm bolts will stretch or break like your case. Thats why Yella Terra is making a 7/16 bolt shaft setup, at around 400+ lbs of spring pressure the bolts will stretch you need to remember the pressure is multiplied over the rocker arm tip. When the ls1 was designed with the conical springs this was to reduce weight over the valve and the need for higher spring pressures but as cams get more lobe intensity the need for more pressure arises. We really never heard of bolt problems till people started running bigger cams and real radical lobes. The weight of the rocker arm is really only important over the valve tip the mass at the fulcrum is not supported by the spring or lifter when in motion. Most good rocker arms are minimully heavier in this area than stock rockers. Increase spring pressure is the only way to reliabley increase rpm range then pushrod flex starts to become a factor its a fine balance.

 

That sucks. How 'bout doing a little research and testing before bringing a product to market. Maybe they figgered these would go on stock engines with stock spring pressures. I guess the bolts are going to either break or pull out and necessitate a little machine work to the heads.....or worse. Ahhhhh shooooot. They sure were purdy sitting in the package. I guess looks ain't everything.

 

Well, I emailed Yella. Hopefully I will hear better news than what I have heard so far.

 

mark me down for a broken intake bolt......ahhh and of course arp not making bolt or studs for us!!!!!!!!!! heli coiled head and using a new one in and crossing my fingers......