The V8 Owners Forum -

Posted: **Wed Jul 25, 2007 6:12 pm**

I have a pair of heads with BIRMAL and the numbers 612571 cast onto them.
I cannot find any HRC numbers anywhere.
Any ideas?

I've just discovered they are either P5b or P6.

I have some bigger later valves. Is it worth having them fitted along with seats?

Posted: **Wed Jul 25, 2007 8:13 pm**

If you port a set of p5 or p6 heads as far as they will go and fit the biggest valves they will take they still won't flow as well as a bog stock set of SD1 or later heads so no don't bother.
Mike

Posted: **Wed Jul 25, 2007 10:11 pm**

Maybe i should get them re-cond and sell them to a P5/6 owner.

Posted: **Wed Jul 25, 2007 10:45 pm**

I shouldn't bother mate, there are hundreds of them around and they can usually be picked up for a tenner or less! Clean 'em up and use 'em for porting practice imo.

The V8 Owners Forum -

Cylinder head question. (Now Sorted)

Cylinder head question. (Now Sorted)