I just ran into this issue when assembling my engine. I'm using GRP Aluminum rods, Ford sized cam in the stock location and 4.5" stroke. Rods 1 and 6 hit lobes on opposite bank. The interference is right where the side of the big end starts to curve around towards the beam and lasts for about 15 degrees of crankshaft rotation. The rod is chasing the cam lobe. The fix will be to trim some material off of this area of the rod. I've noticed on R and R rods that they have an assymetrical profile on the big ends to aid in clearing the cam. I've mentioned this to Mike at T/A so that he may caution others can avoid this situation. I didn't experience with my other engine assuming it was because it was only a 4.4 stroke and R & R rods. Stuff happens. This block is really nice to work with. No band-aids required. Must be what it is like to build a chevy.