I own a MGB-GT, a beautiful noisy (interior noise) LBC. (You roadster
owners calm down! When your top is up or your detachable top is on, you're
just as noisy!) I would like to add a free flow exhaust to my car, but as
far as I'm concerned the noise level of the original exhaust system is the
limit of what I want to endure (I like to talk to the passenger not yell at
I read Peter Burgess' book on power tuning the MGB. A very good book that
answered MANY questions I had.
Both Burgess and John Twist strongly suggest keeping the original cast
iron exhaust manifold. Twist insists that ALL after market tube headers
leak and both these guys determined these headers are noisy compared to the
original cast iron manifolds and with no noticeable increase in power.
Most, if not all full flow exhaust systems use only one muffler (I
understand that in the original system that the front silencer reduces the
low frequency noise and the rear resonator reduces the unpleasant high
I want to be able to increase my SU intake flow but, all this tells me
that any full flow exhaust system must be louder than the original system.
I would like to be able to keep down the noise, preserve the beautiful
sound, retain the cast iron manifold, AND be able to take advantage of the
increased intake flow. And if you can arrange it, a gorgeous blond I can
whisper to. That's all I want.