Re: Bolt in?
Some years in there would help...but if it is an '81-'91 Suburban which it sounds like (454 FI, so 87+ and 2WD) then yeah, you can swap it. Might need a conversion ujoint, but that'll be about it.
As for the mill, I'm not sure. Depending on what year the K5 is will depend on how similar the wiring will be. Since the 454 is FI then there's a half-assed computer involved.