Originally Posted by Hpimichael
so is there a base exhaust length for all engines???
No, the lenght is based on the specs of the engine like boring, exhaust port height etc. Also the cooling and shape of the exhaust can make differences in the ideal length. Thats why you can play with several manifolds.
Beside that, with playing with the exhaust length you can determ in which rpm range the maximum powerband is.