I've encountered problems in disconnecting the split exhaust pipe from the exhaust manifold studs. The problem is that there is a lot of extremely high temperatures around there from the exhaust gases. If the engine hasn't been out of your chrome bumper MGB for several years, your six 1/2" nuts may tend to 'freeze up', and it's very easy to break off studs when trying to turn them. If a stud breaks you'll probably have to carry the cast-iron manifold to the shop to be drilled out and re-threaded, in addition to ordering a new stud.

Sometimes it may be easier to avoid the whole problem by simply leaving the exhaust manifold attached to the exhaust pipe and just disconnect the manifold from the engine. This can be easily accomplished by backing out the two outside exhaust manifold studs in the cylinder head (by tightening two nuts against each other to facilitate their removal), then removing the intake manifold. The exhaust manifold and exhaust system can then be pushed aside to allow you to get the head off. Remember to place a new manifold gasket onto the remaining manifold studs before the head is placed back on the car.

Also remember to use solid brass nuts, which are less prone to seize, when reinstalling the manifold. I've not broken any studs since switching to brass nuts, and a recent clutch change was made much easier than previously due to this one simple change.

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