[Fot] MORE spitfire h/gasket question

[marty sukey]

Ah perfect timing for this subject as I am getting ready to start on my next
Spitfire engine project. Grenade number 2 if you will. I will be making
another attempt at a MK3 1296.  A while ago it was suggested to me that I
counter bore the face of the block to accept a later head gasket out of the
1500 engines. That they would hold up better than the non-recessed earlier
gaskets. If this is indeed the path to take, does anybody happen to have the
dimensions (depth and diameter) of the recess on a 1500 spit engine?
Opinions/suggestions welcome :)

Marty