I don’t know how many times you are going to do this job but this tool Makes the job so much easier. I have one for doing Chevies too. View attachment 1715894798
I got one from Goodson similar to that. It was a lot cheaper than that, but that was like 20yrs ago, too.
I have a 3in travel dial indicator which can reach in there, easier. I also have multiple mag bases and adjustable attachments to arrange it just so. They also make different replaceable tips for the indicator which can help, also. For a small block mope you'll need a set of offset woodruff keys, if you have to adjust the c/l.