[RonP]

I worked with/at Kromerkraft in the late 90's & early 00's. Everything we built in that era was merge collectors with the tower in the middle to make the flow path more streamlined, occasionally megaphone collectors. Our experience from customer to customer was maybe a max of 0.05 seconds improvement. Generally, 0.02 or 0.03 made for a happy customer. Sometimes what the car wants on the track is not exactly the same as what the dyno wants. One occasion, we had a Super Stock engine builder request two sets of headers, one with 2 steps and one with 3 steps. The dyno liked the 3 step and track liked the 2 step. My guess for the merge collectors is that won't hurt, but may not help. Generally, we found that each customer had to be treated individually for his particular setup.