Can someone recomend a good set of Heads to replace my stock Heads, Maybe something that will give me a little Gidiup and help with my Nitrous Application.
This is one of those of questions where you will get alot of different answers, everyone has their own opinion. My favs are the Canfields, but then again thats what I have on my car. Before these I had a set of iron GT40s with a mild port job. Can't tell you exactly how much power I picked up because I did alot of other work at the same time. There are lots of good heads out there. Trick Flow, Edellbrock, Dart. It just depends on what you are putting them on and how much you want to spend. If you are going with a mild setup the GT40s are good and the price isn't bad, if you want to run an 8 sec 1/4 mile you need a set of Yates.
Any of the above mentioned heads will be fine for your stock bottom end . I think the GT-40 heads are the best bang for your buck heads . Cheap and easy to get a hold of .
I would go with the aluminum castings (I assume based on your sig you're talking about the Explorer iron based "P" versions) over the GT40's. Not so much because they will net you that much more power than the iron GT40's (although some of them like say the AFR165 can net you as much as another 40hp in N/A trim and even more with a power adder by comparison), but because you get the added benefit of knocking 40-45lbs off the front end of the car.
Its easier to add power than it is to remove weight, but by going with an aluminum head, you can do both.
as for iron vs aluminum. the material aspect they each have their pros and cons.
like iron is less prone to warpage, but it heavier, takes longer to port.
alum is more prone to warp, easier to port and alot lighter.
almost all the good aftermarket heads you will see are aluminum thats where all the R&D is now, the biggest advantage is the weight, the weight difference b/w a set of iron heads and alum heads is insane.
aluminum all the way.
or a budget alterative is some GT40 iron heads, pretty cheap, world products made some iron heads fully assembled for under 1000$ but flow wise all the aluminum counterparts outflow them out of the box.