My experience with W2 rockers, is that they DONT oil the pushrods correctly IF they are that far away from the adjuster. Went through this exact scenario 4 or 5 years ago on a W2 340 I machined for a buddy. I showed him how to measure pushrod length after the engine was assembled, but he mis calculated the exhaust pushrod length. It burned the tips exactly like yours. I measured and ordered the 2nd set, and no more problems. Been beat on heavily since, lash hasn't moved in 4 years at least.