They are different in the way the casting is and the CNC work on the heads. They are very impressive but have some flaws. My friend could not get his Dynatech downswepts to bolt up. They were the bigger tube header. Some say the smaller tubes will bolt up. They also tend to hold more oil in the head which created a lot of overflow issue with his vacuum pump. That was corrected with a tall valve cover and baffles. All in all, the performance is very impressive. He has 2003 Worthy 230" swingarm. The 565 is running 7.40's/50's with this set up.