are those pics of the ACTUAL engine in your Nova?
It looks to be a late model engine with the casting marks and center bolt covers..
Could be a 305.
Did you check the casting #'s before you purchased it?
If the rest of the drive train can't handle the 400hp that your after, it could break things quickly.
A late model 6.0 (Ls style block), level-10 200r4, and a fab-9 rear 4 link (or Hotrods to hell suspension) and you'll be very happy!