Thanks mate, what head gasket would i be best to use? I was using grp a cossie b4 when engine was standard. Block is currently in machine shop getting bored for the o/s pistons. Once its back i will cc the pistons and do all the calculations but 1mm was roughly what i had in mind. I measured the head volume to be 50cc.
I also have a 2wd spray bar here ready

do you know if the pistons sit flush in the standard un skimmed pinto block?