Tri-Y Headers or 3-collector headers are designed for maximum performance for a specific engine combination, desired engine RPM, race track, etc. For a Tri-Y header to have the proper effect the cylinder firing order must be properly paired so that the next firing cylinder is separated. Sequential pairing is optimum, example the LT-1 firing order is 1-8-7-2-6-5-4-3 so pairing of the 1 & 5 and 3 & 7 cylinders on the passenger side and the 2 & 4 and 6 & 8 cylinders on the driver’s side would be the proper sequence. You also need to have the proper primary size for the engine displacement and application. The collectors also need specific convergent angles (7-20 degrees) for optimum efficiency and cannot be a random bend angle. We have seen horsepower and torque numbers dramatically affected by these angles in Tri-Y headers. In our testing we have found the primary head pipes (First Section) must be between 17” – 21” in length for proper pulse scavenging, anything more than this has shown no increase in performance.

The data we have collected over the years proves the Tri-Y design does have advantages in race applications with the right vehicle and the right engine combination on the right track. Most professional teams will have several sets of headers and engine combinations for different tracks and conditions.

Conclusion Here comes the tough part. Unlike the previous tests where we were able to separate oil pan and rocker arm performance from the rest of the engine package, header performance is critically dependent upon the design and performance of the rest of your intake and exhaust system. For example, had we used a single-plane intake manifold instead of our Weiand dual-plane intake, the results could have been completely different. The same holds true if we had used a different set of cylinder heads, camshaft, and even the length of the exhaust pipe after the header collectors.

So, while we cannot unequivocally say that Tri-Y headers are the best design for your race engine, we can say that small changes in the way a set of headers are constructed can have a significant effect on your engine's performance. In fact, finding the set of the headers that best compliments your engine package can significantly improve power.