I installed a tfs1 cam a few weeks ago and am a little disappointed with the results. The car sounds great and has a strong pull at 3000rpms but begins to lose power above 4500rpms. I was being cheap and didn't replace the valve springs on my 97 explorer gt40 iron heads. I read they were rated to .550 lift so i thought i would be ok. Is it possible I am getting valve float? My car pulls almost the same as the stocker up in these rpms and its pretty disappointing because I was looking for some top end power. Any thoughts?