I did a before and after when I installed headers on my CJ auto car. Car had CJ, 65mm throttle body, jlt, upr off road x-pipe, driveshaft e85. Made 427whp and 370wtrq. Only change was installing the kooks 1 7/8th headers and their off road x-pipe same tune. Made 443whp and 390wtrq. Same dyno...
Had some fun with a friend of mines Camaro. I was testing out my CJ manifold seeing how much of a difference it made. Safe to say I'm happy with it. He use to beat me by half a car before the manifold and corn. http://youtu.be/Fb2YVSy6ogs