Head, providing you already have a decent header and air filter.
Apparently you need to adapt the dowel holes for the predator, but it should be fairly self explanatory and be able to be done with some drill bits.
Maybe get some nice 1:1.3 stamped rockers in there too? They are much better bang for your buck than a new cam. Or diy some like I did. Weld up the rocker and existing push rod dimple, and drill some new holes closer to the pivot. Mine work perfectly!!!