We will have to disagree.
I think they were largely White Anglo-Saxon Protestant. (WASP)
The Catholics did the one thing that could reverse the stereotypes. Their relentless insistance on education for their children pulled them ahead of their contemporaries and solidly into the middle class.
There are still legacy Democratic / Catholic strongholds but they are susceptable. I am part of a group that is building the next generation of the Republican Party. We are hunting down the bright young kids with leadership ability and dragging them into the Party. When I am given a name and punch someone's doorbell the chances are better than even that I will be talking to a Catholic.
The Reagan Revolution was Catholic. The campaign was by Catholics and aimed at Catholics. Reagan's philosophy and base was Western Republican (Mormon) but it was Catholics that ground out the Reagan agenda.