Boy that is big money for the rockers, ouch!
The reason I mentioned rocker arm shaft breakage is it's actully some what common on the FE's. You really need to be extra careful on the end stands for getting the right height adjustment, etc. before you torque them down. I THINK the stock rocker arm assembly didn't even use good end stands, it's an after market "gotta have 'em" thing today, especially if your running higher spring pressures. Which you WILL be with roller rockers.