Yep Paul you can do that. Or elongate the hole. Really, its just a matter of how much compromise you want to do. I have 5 engines sitting in my shop that have these holes drilled by the previous owner. All he did was measure 3 inches between the two holes, then 3/4" from the front of the plate. Its pretty close, but its up to you how far you want to go with 'close'. So what I did before finding out about how to do it right can be seen here:
http://devestechnet.com/Images/Projects/Project1959235/Project5923562lg.jpgclick on the picture and notice the two dimples made by a punch.
Had I not learned the correct way, that is where the holes would be centered. Point being, its not too far off, and maybe everything would be fine. If the plate is 1/8" thick, and I do not know off hand, then subtract that number from the .955 and you will be better off than the dimples I put in mine. Not sure its worth overthinking really. That is, unless there are other reasons to take the engine apart.
Paul, I am not sure how many percent you are degrading that bolt by halving the head. This is why maybe a weld nut on that side or both sides and bolt from underneath until you get it apart. Removing weld nuts are 101. Good luck guys! All part of the learning process. The nice thing about steel is, you can weld that hole shut later on, and do it right. No harm, no foul.
