Hey guys, update on my 498" Bonneville bullet using THE Block. I cut the collectors to 13.4" and had them Jet Hot coated. Finally got it on the dyno at Best Machine. This endurance build with a single Quick Fuel Dominator made 947hp at 7400rpm and 690tq at 6800rpm through my first time built 2 1/4"-2 3/8"-4" collector stepped headers that fit inside the frame rails of my Daytona clone. I now wish I'd have gone with the recommendation of a 4 1/2" collector. Engine ran better with a 4" to 5" adaptor on the collector. I tried 4" extensions at 54" long in hopes of getting the exhaust out from under yhe car for speed runs and it killed 35 hp. Will try 5" extensions and see if that works.