I currently have the Tri-Y's in mine also (backed up by a 2 1/2" exhaust ,crosssovers and flowmasters). The Tri-Y's are now 20 years old and a little too rusty. The real issue is that when I hit certain straightaways that I can come into fast (back straight with chicane at Watkins Glen or main straight at Limerock) I am running out of top end. I have a very tricked out Holley up front (webber jets etc..) and the O2 sensor doesn't go too lean. What carb CFm do you run and what is the diameter of your exhaust tubes. Have you tried a x-pipe crossover.
Thanks, Bob.