[mickmate]

Hi Jim, interesting score. I think you'll find the pan rail repair is common on these motors. The one in the car here now has had that repair. It won't be a problem if it's been done properly. It was more a leaking problem than integrity anyway.
The later bores were squared off for strength on the water jacket or outside, the earlier ones like you have were round or concentric on ID to OD. With the improvements in metallurgy and machining tolerances if the sleeves have also been done correctly that will be no worries.
Cheers mate.