If it were me, I would go with the trickflow stage 2 cam.
Any performance related aluminum head is going to be a huge improvement over the stock ones, so its just a matter of what you can afford and which you prefer. Myself, I like the AFR 185's or the 165's. They are a little more than your average head price wise but definitly worth it. When I put heads on my 351W last year i went with the Brodix ST5.0R's and I really like them, I also used the cam I mentioned above. (Trickflow Stage 2)
Here is what my combo sounds like....