It did very little for my truck too. But I do think it varies a little from engine to engine. From what I have seen our base timing varies some from the factory-anywahere form 14-16 deg I've seen reports. So depending where your baseline is it might make it more noticeable, but on most trucks it's still not too much. However if you can do it for free like my dealer did, the slight gains are fine. Also if you can find any Uprev tuned guys in your area they can do the advance for you too.