What do you guys thank about stepped Headers was looking at 2 1/8 to 2 1/4 and my be one more step. Not shure how long i need to start with or what the over all Length needs to be before the collector. What are your thoughts 555 engine 7500 to 8500 RPM
Using Larry Meaux's "Pipe Max" program I input some generic numbers. If you give me the exact cam specs, bore and stroke, compression ratio, expected V.E. or power output, Valve sizes, head flow, rod length, etc. I can input those numbers and it will be closer. I used 14:1 compression, 288/296 degree cam @ .050 with .800" lift. 555 cubic inches power range 6500-8000. Single size primary header 2 3/8" primary 26 1/2 to 29" long with 4" collector 14 1/2" long. Single step primary header 2 1/4" 1st stage 2 3/8 second stage both 13.2 to 14.6" long with 4" collector 14 1/2" long. collector specs are for conventional 4 into 1 straight tube. Collector sizing more important than primary sizing. If you want to use a merge style collector with diffuser specs are 3.66" at choke and 4.66" at end of taper, overall length from end of primary 14 1/2". Just FYI, a 555 will need heads that flow roughly 470 cfm and closer to .900" lift to make power to 8000 rpm. These are generic numbers and would be closer with more information about the build. If you really want the best headers possible, call Burns Stainless with all of your EXACT specifications, pay the $75 charge and have them design a set of headers for you. They will tell you the available options and what their recommendations are. If you buy the parts from them they will credit the $75 Good luck ---------- Mark
