yep. X block comes 3.91 ish bore. So 30 over would be 3.94
They usually will go 4.070 with no issues. I had one i ran at 4.100 and had enough at that bore for a freshen with a custom piston( would try to avoid going all the way out to 4.125)
I am not a concrete in the block guy, so I prefer Lots of meat and not a questionable bandaid