I have been running tunnel rams on engines for more than 30yrs. THEY will almost always make more power! In fact every one that I have done made more. Currently, I have one on a bb with rpm heads and a flat tappet cam running a best of 5.88 at almost 117mph footbraking. I am anxious to see what it does when we transbrake it. that equates to about 750hp. car weighs about 2850