Thanks, all.
Oh, here is what I was asking about.
Russ
Yes, that bracket measured out to .125 (nominal). As mentioned the shape has a lot to do with the strength. Try elevating a book with a sheet of paper and you get nowhere. Cut the paper in 1" strips, tape the ends together to make circles and it is well supported. It is all about the shape.
You might want to look at how the 302 V-8 was put in the Mustang II as I assume a 351 in a later Pinto would be similar. BTW, the bracket above (post #6, pic #2) is a '74-up bracket welded into a '73 for a 2.3T conversion. So, don't use that as a guide for placement.