experiencing valve float?

[spyder2455]

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?

 

[DMAN302]

tired springs can definately be an issue in the upper RPM's...sounds like you know what needs to be done. Good time to have the heads ported while there off.

 

[legalize420]

what rockers do you have? im at .529 with stock springs.

 

[spyder2455]

I'm using the stock rockers.

 

[86bluecobra]

i would say that it is time to replace the valve springs. There has been tests done time and time again that show upwards of 50 hp lose in the top end because of improper or tired valve springs.