What do you have done to the engine? Adding a cam without any other mods is going to be a waste of time. You should wait and do a Heads/Cam/Intake swap. Might as well do it right the first time.
Throwing a cam on a stock motor, as stated above, wont do anything for you. Stock motors with cams sound stupid when they open up too, you can hear that they have stock heads, sounds like it runs into a wall up top.
its an explorer motor with the gt40 heads. I heard that the exploder cam is crap and that I need to replace it before it goes into my stang. I also plan to run a cobra intake as well
Most cams that have that "lope" we all desire are a little tough on the street the lope comes from the lobe seperation and the duration not so much the lift. But you have a roller cam I would suggest looking into the names like comp, crane, lunati, Iskey, abc ford cams etc... They all will give info on idle quality .Stay away from edelbrock they are not made by edelbrock and they have a lot of problems with lifters eating lobes. If you do a cam try to stay under 500 lift even 500 pushes the valve train hard and you can have valve clearence problems. And as I said before the more lope the tougher it is for a daily driver.
For a street car, bang for the buck for an off the shelf cam the stage 1 is great. The E is not a bad choice but the stage 1 is better and I have had both.
Kevin