Well on my ranger, (2.3 and stick) I did a few things that helped it out a little. First, I took out that stupid baffle in the stock air pipe and cut the tube off right where it gets bigger, attatched MAF sensor to the tube and added a cone filter. Next I seafoamed it which actually made more of a difference then I thought (she is alot snappier on the revs). I then replaced my belt, since it broke, and re-timed it. She is actually running 4 degrees before top dead center and she seems to really like it. None of these will make her do wheelies, but you could tell a difference with each one.
Got a quick question. If I was to buy a used head, surface it, gasket match it, replace springs etc, what sort of power would it give it? I have never had head work done on anything that I have owned so Im kind of curious.