I agree, there is no way it could hurt your top end. It doesnt say anything about it on the description of the product because it does not create any noteable gain. Less than 1hp.

 

Some say up to 15, some say up to 20.... But doubt if the average gain is very much at all. Think the numbers they claim are for certain trucks/engines, might not be for Chevys. Herad they give a noticeable gain on the 88-98 TBI's. But that's a diff. engine.

 

I have installed a Helix spacer on my 2004 2500HD 6.0L. Installation was no problem and the truck seems to respond better. I have not driven it enough to see about the fuel economy but it seems to work fine so far. One note of caution for people looking to install a spacer: If you do not have an electric fan you HAVE to check the clearence between the bend in your air intake tube and your fan shroud. I had already bought the spacer before I realized my K&N intake would not clear the fan shroud. So I had to by an electric fan.