heater core flow restrictor ?

[rickf]

I just got a Napa heater core for 64 "fresh air" heater. I was musing over the hose mount tubes, they are not quite aligned right. That's when I noticed a plastic (of some sort) plug inside the 5/8 inch tube, with about a 1/4 inch hole in it. I tried to pull it out, but couldn't get it to budge.

The core that came out doesn't have one of these, nor did the orignial core that came out some 15 or 20 years ago.

I'm having a hard time accepting that this is some sort of technological advancement, that heaters work better with the flow restricted. But then, I'm no thermal engineer.

What I think it is, is some sort of forming or assembly tooling that broke off, and an inept inspector passed it anyway.

What do you think?