I'll measure the caliper pistons for you as soon as the black paint dries..lol. These rotors are 14.17 tho.

Ah man that sucks! This is your daily driver right? From what I hear I'd avoid the 408 for longevity concerns. It'd be better in something that only saw a few thousand miles a year. So for you i figure the 370 would be best. I know in my head it'd suck to spend all that money on a short block and not gain anymore cubes.
Are you still running stock heads?
What can you pick up a gen4 6.0 for? They seem to hold up really well up to about 20psi. I picked up a ly6 last week for 700 with bad cam bearings I plan on using for my turbo s10 project, itll be on 12psi daily and 17-18 for high boost.
Oh I thought this truck was driven a lot more than that. For only 3k miles a year I'd definitely go with the 408. But if you can upgrade a cheap 6.0 then that seems like a much cheaper route.
Although the LY6 and L96 both come with square port heads so would the blower be able to fit those?