Martyn,
Wow, where to start?? I would be delighted to look that one up for you, if I could just visualise it.
I've had my pony out once since 1972 for other work...hey, this would be the head gasket???????
If so, part# 6F4201 (U series), 2A3430 (J series)
Hope that is what you were looking for.
Eric