Best advice: Don't try to re-invent the wheel. Unless you are going racing, use
your original cast iron manifold and down pipes with Jet-Hot (or similar) high
temp coating. LCB headers give a little more power at the top of the RPM range,
but you lose in the middle. The consensus among MGB owners on various
electronic lists that I've seen is that the big-bore Peco is the best buy, but
strip the coating off and repaint it with proper high-temp exhaust paint before
you install it. Exhaust changes alone will not gain you much more power. The
most bang for the buck is a properly gas-flowed head from Peter Burgess in the
UK or Mike Brown (Seven Shop Ltd.) in Oregon. The Maniflow intake manifold is
highly recommended if you are really serious about improving your gas flow.
Then, of course, you will need a warmer camshaft, hand-selected lifters,
chromalloy pushrods, maybe roller rocker arms, a pair of flowed HIF4 carbs,
larger, flat-top pistons (and an over-bore), a new distributor with the correct
advance curve, and some tuning time on a dyno. And then you have to go to work
upgrading your suspension and brakes. It's a disease.....I know, I've got it
too.
A MUCH bigger bang for the buck would be one of the supercharger systems
available from Moss Motors (USA) or Hi-Flow Engineering in NZ. These are
supposed to be a week-end rather than a Winter long project, and cost about the
same as (or less than) building a hot, normally-aspirated engine.
~Jerry
> Ok, I'm looking for exhaust experiences. I have a 1970 MGB and I'm looking to
> improve the exhaust. From what I've read, there isn't actually any gain from
>a
> new header except for ease of joining up a 2" exhaust system, is this right?
>If
> it isn't right are the LCB type the best and is there much difference between
> types, like Peco and Mani-flow...?
>
> As far as exhaust goes, I'm looking for something that is not too noisy but
>is a
> definite performance boost. Any recommendations here? I'm thinking Peco or
>Ansa
> and it seems Peco is cheaper.
>
> Thank you,
>
> Scott
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