Roller Block: Pushrods Rubbing Against Head
I had to go through this putting Edelbrock LA heads on my Magnum block, I mocked up the valve train before installing the heads permanently and there was no way in heck the pushrods wouldn't hit the tubes in the heads unless I clearanced them. Same exact issue, taller roller lifters moved the bottoms of the pushrods out towards the cylinders. I did get custom- length pushrods but that was to achieve the right lifter preload.
Since my heads are aluminum I got away with using a dremel with a cutting bit, a legit die grinder with carbide bits would have been much better though.
FWIW it's got about 1500 miles on it so far with no issues, took off my valve covers last night and everything looked perfect.