Ya know if you were able to get that header length to work out right at 13-1/2" you would be hitting a power sweet spot with the 3.2

with the baffles set to what lenght is that 13.5 deal?

I have extra that i am going to test with to find out what works best for my needs on the test stand with the vess props then install the set up in the plane.

Rcpilet, That sounds worse than mine, as only the tip of my middle finger is sore this morning. But like you, I was very surprised and learned a lot from that one firing.