[Brian]

Lawrie, I've just bored mine a very conservative 0.125", and there is still plenty of thickness left; I'd say the cyl walls are still at least 1/4" thick at top using the old two finger measuring gauge between cyl wall and water jacket. In my experience, these C69A's have the thickest cyl walls of any of the 59 series blocks, I doubt you'll find any other block more suitable for boring big. No mate, I'm not going to nationals; I'm not in the club, I'm too much of a hoon!! Brian