Identifying type of head on a Vauxhall engine

[turbopug]

As my name suggests, I'm not a Vauxhall person.

Can anyone tell me how to tell if a red top engine has a Coscast or GM head?

[Bacon Is Proof]

http://lmgtfy.com/?q=Can+anyone+tell+me+how+to+tel...

[turbopug]

[DaveH23]

Bacon Is Proof said:

http://lmgtfy.com/?q=Can+anyone+tell+me+how+to+tel...

Perfect......

The first result google finds is this thread.