1970 340 SHORTBLOCK OR BOAT ANCHOR?

I'm not a welder by far, but I'd put a dowel pin back in the hole, braze or weld back around that and then just leave the side of the bolt hole open after grinding it back round at the dowel weld/braze. Then I'd get an ARP or McMasterCarr hardened STUD, nut and washer to use there (the threads are in the bellhousing) instead of the factory bolt. I wouldn't be scared of it one bit, as once it's alogned with the dowel, it is under compression as mentioned above.