depending on the block, you could just have to drill and tap (id advise having the machinist doing this) and put a spyder and roller lifters in, then i believe (don't know, someone else chime in?) you might have to get a custom type of cam with a lower base circle? read that somewhere at some point...or get the retrofit lifters.
anyway, a great 351 hci would be AFR 185s or TFS twisted wedge's with a custom cam and a holley systemax or TFS R intake with supporting mods. lots of expense there though...