SCAT or Eagle rods??

the scat I beams are made from 4340 steel

Correct. I have been in touch with a few people who used the Scat I-beams with a 4" crank and no grinding on the block was needed. My block is at the shop now and my machinist checked my new Scat I-beam rods over for my stroker and he liked what he saw. There was a flaw in my Scat crank but as soon as that is resolved rod clearance will be checked on my block. I don't expect any grinding will be needed.