Marc,
The difference between the two exhaust manifolds
is the thickness of the mounting flange at the head.
Early manifolds had a thick flange, midyears had a
thin flange (or vice-versa, cant remember...)
Late B's have a single casting that combines both
manifolds into one lump. These are another kettle
of fish altogether.
WRT the early and midyear manifolds, if you use
the corresponding intake you will not have any
problems. If you try to mix years, the mounting
ears of the I/E manifolds will not be in the same
plane: this will become obvious when you try to
refit the cast donut washers, one of the manifolds
will flop around.
If you can't find the correct manifold, 5 minutes
with an angle grinder/dremmel/flat file will
solve the problem. Just dont grind too much off.
If you have ever wondered what the blurb 'some hand
fitting' may be required in those MGB header ads
means...
The headpipe to manifold area is identical for
early and midyear types. Remember when doing
exhaust work- brass nuts, anti-sieze compound and
Kroil are your best friends.
--Scott
Scott Hower -> howersl@mailexcite.com
73 MGB
78 Midget
> I have a 66 BGT with violently damaged exhaust
> headpipe. The engine is a later 5 main bearing
> block with no engine ID plate. My catalogues
> list two exhaust manifolds. One 18G to 18GK
> engines and the other 18V on. The drawings of
> the headpipes look different at the headpipe to
> manifold connection flanges. My headpipe looks
> most like the later version and my exhaust manifold
> has the numbers 12H 709 or /09 on front fork.
> Will either head pipe fit either manifold?
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