If you want to get the most bang for your buck in building a 289, your first purchase should be a good set of heads. I have had LOTS of suucess with AFR almuminum heads and happen to have a NEW set for sale that I will not be using. Take a look if your interested. Do the research and you'll see that these are the BEST.
Go here to see them:
http://www.inficad.com/~moneymanager/partsforsale.htm
They will bolt right on.
Doc