CMB 65 pipe length

[Dr Hydro]

I have an old CMB 65 Gran Prix(slightly modded) and was wondering what the pipe length should be. I cleaned the header with a wire wheel and now can't tell where the pipe used to be. DUH. Been a while since I ran it. Thanks in advance. Jim Fullmer

 

[Hydro Junkie]

Most of the people I've talked to start out around 11.5 to 12 inches. I think that also depends on the boat, pipe, fuel and set up

 

[jeff baham]

jim, my twin cmb 67 evo -1's with cooper pipes is set at 11 inches, from plug to first well band on pipe, plus my cmb67 purple head with a cmb fat belly pipe was set at 10 3/4 ,from plug to weld of pipe. running 40% nitro. these engine are in riggers.