I have seen three different aproaches with the big cap distributor.
One said he had to massage the firewall a tiny bit, and another said it just barely cleared the firewall.
I guess the difference could have been worn motor mounts.
One of them was in a Dart and it hit his wiper motor.
Not real comforting for you probably.
One thing about the small cap "all in one" is that a lot of people poo poo them as Chinese junk, but I have never seen a legitimate complaint about them by anyone.
One guy said his was bad out of the box, but got a new one sent and no problem.