Just my opinion here but I don't byy not have to change the valve springs with any upgraded cam...you will sooner than later...those stock springs are only to designed to handle the stock lift and won't be able to create enough pressure to maintain proper function and the valves will start floating...

I say change the valve spring with any cam install!

 

The hot rods only change the lift by 1mm, hardly enough to need new springs. Not only that, the same engineer who designed the hot rods made the stock cam. I think these guys know what's good for the engine.

But I can understand why some hesitate at the thought of not replacing the springs. This is new new thing to do and in the "old days" cams always needed new springs b/c the lift was so much higher and it wasn't so expensive to change the springs. But with these newer engines, changing the springs is not only a PITA but very expensive so it makes more sense to design a cam that doesn't need a spring swap.

 

also alot of these dynos are early on when people started putting these Comp Spr's on. now with a good tune i have seen 40+ with these cams N/A. Also Doug at Bamachips said he tuned one with Nsr Stage II's and got 25-32 rwhp through out the entire rpm band with no lose of low end power.