Done a search but can't really find anything conclusive on how to ID an Impreza head, apart from taking it off the car and to pieces, which I don't want to do.

Looking at the top of the engine now, I can see on the gasket face between the two inlet ports, there is a number scribed in the metal. And unhappily for me, the left and right heads show two completely different numbers in two different scribing styles, although apparently they were 'STi 5' heads (according to my crooked engine builder who went bust).

But maybe these are just random numbers? Surely they must have a type code somewhere really obvious so they can be identified easily?

If this is not possible, I may be having the rocker cover and cam covers off soon, although again that's a job I'd rather not do. Will the answers be revealed within?

Cheers!

 

Well the are most definitly not STi "5" as I believe your car is a 98 and those head / inlet manifold interface look phase 1~1.5.. not phase 2 ie. STi5..
They could however be STi3 or 4..

If you remove the cam cover to extra that broken bolt and post a picture of the valve shims then it would be easy to tell.. although you might need to remove a cam to be sure.

Simon

 

Yes AFAIK it's all phase 1/1.5. I'll have a crack at taking the rocker cover off today then.