Exactly , if anything you want to restrict the oil going to all the cam journals except for #4 , the first block I did this to I loctited set screws with a smaller hole drilled down the middle , now I just drill a smaller hole in a different spot and put the smaller hole over the passage.

Definitely check those angled holes , I had a 400 block that had partially blocked holes going down to the crank from the main galley , I open them up to 9/32" with a reamer per the recommendations I got from Herb McCandless years ago.