the reason I did not metion the HSN is that it screams at full throttle, almost sounds like its revving to max rpm with great smoke trails. The LSN is whats giving me issues. I like it a little lean but then it sounds like it loads up and the RPM's increase after a few seconds after I let off throttle. This thing ran great on Trinity fuel and was easy to tune but I went with a respected recommendation to get o'donnels. Has anyone switched to or from o'don's and notice any of the issues I have. I will get it tuned with a little more time but its not as easy as with the last fuel and I was just checking if that was it.