Well if "slightly" heavier springs were added it sounds like the first one's may have coil bound. Possible a pushrod is slightly bent. Even tho all top shelf parts were used they need to be matched correctly. You really need to find out the cam specs vs the old and new springs that have been installed to be certain they are up for the job. Also on the rocker assys are there springs or spacers between the rocker arms? And are they aftermarket rockers on oem stands and shafts? Or a nice setup with end stands and good HD shafts? There can be to many variables in "top shelf". These are the things you need to know to be certain it does not happen again. Things happen even from the best of builders. Even the parts themselves although the best money can buy still can have issues and defects or assy problems. Could be a crappy batch of pushrods. With the deck and heads milled that changes the geometry a bit. And they might have been trying to get away with using some stock parts that may not been the right choice. So please try to get the cam specs and rocker assy details. Even if you take a pic of the rocker assy and offending pushrod and post it. That would help.


G.