What is the difference between 4.2 S1 and S2/3 head gaskets

[phoenix]

I am just about to rebuild an S1 4.2 E Type and I do not know the difference in S1 and S2 gaskets. Is it the head gasket itself or the others . Neither Barratts or Robey have the S1head gaskets in stock.

[christopher storey]

The head gasket changed fundamentally when the short stud block ceased and was replaced by the long stud block . The major change was that the rear of the block and head were extended by about 3 cms and additional water passages were put in. The long stud block is instantly recognisable by the fact it has 5 core plugs on the exhaust side of the block, rather than the 3 of the earlier engines . Note also that there are some cars where in the 60 years since they were made have become victims of "pick and mix" modification where the earlier head is used with the later block and vice versa, water passages being blocked off to suit