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What is the best casting to start with when modifying a Grey motor head?
I have a few here and I hot tanked a std, un machined head today with intentions of porting it, fitting red motor valves, duel springs etc.
I know the early ones had the GMH logo on them, later heads had Holden, EJ heads have a 2nd water outlet etc but id there a definite "must have" head to use?
Also, has anyone got any photos of a sectioned grey head to show water jackets and port wall thickness? If I have too I will section a grey head but I am sure someone out there has done it in the past?
Cheers
DW.

they are all pox

As mentioned on Facebook but will put here for others aswell

GMH is the later ones. Not sure which is better the later start with a larger valve I believe, so I'd guess that one.

Later heads normally have 2 heater ports on top...either way it doesnt matter. The very early heads do have slightly different cast with less between the water jackets. Biggest problem is cracks or corrosion these days..best to test it before machining.

Headstud: http://www.headstuddevelopment.com is well known for Grey motor heads but there are many other people that will port and flow bench them aswell.

I picked up my EJ head and Speco manifold from Hydroblast today, they look like new now.