In your situation, the little pipe is the bottleneck in for the unrestricted, and the blue plate is the bottleneck for the big pipe.is there a difference one track runs a plate (big pipe) other track runs no plate but requires a small pipe... restriction coming or going....
So i read into it more than you actually said. I ordered one i can cc it when it arrives.I never said the 181 was a small runner. I simply said at that time which was Jan of 2018 that the 181 was the best head to date for plate engines. This came after an entire season (2017) of testing and customers running the 181.
I still think the 181 was one of the best heads to date, it is rivaled by the 223.