Mike,
First of all it is very common for any double roller type chain to rub on the center oil galley area on those blocks. I have gotten in the habit of taking the die grinder to almost all of them before final cleaning.
There is a "kit" available that makes it real easy to use the late model retaining plate setup in the old blocks. I have done 5 of them now and had no problems at all. You can do it yourself if you don't mind some careful measuring but the kit that Gary has makes it a bunch easier. Here is a link to the post on the Team Chevelle forum that describes it:
https://www.chevelles.com/threads/sb...-block.903098/
Read the entire thread, there are pictures that show the process. Gary sells the fixture in a kit and I can get in touch with him if you are interested.
Once you start using this setup you will never want to mess with a cam button again
