91V8Redbird

I currently own a 91 Firebird, and have done all the basics, (intake, exhaust, EBL, etc.). Although my engine has just over 100,000 miles on it, it seems to run strong and has been pretty trouble free. I would like to consider a Vortec head swap, but I have a couple of questions. My friend that has rebuilt many motors tells me that adding new heads to my old motor will cause problems on the bottom end. He says if I'm going to do that I'll at least have to do a re-ring and bearing bottom end rebuild. Any opinions on that statement?
Also what kind of cam could I run with vortec heads on a 305, I know the LT1 cam is the most popular swap, but could I or should I be running a hotter cam with the vortec heads? One more, are 1.6 ratio roller rocker arms a good idea in Vortec heads? On the intake, the exhaust, or both?