
When I found my car, chassis 152 252, it had no heater pipes to speak of. The engine was a genuine VW rebuilt engine from the 70's with apparently a later style heater box. I could not get things to hook up whatsoever.
Andy Holmes bailed me out on this one. He found these genuine VW Type 3 adapter rings on the Samba, part number 311 255 113.

It turns out they worked perfectly for my situation and I can now heat the interior of my car. I slid them into the flexible pipes and they now attach with no worries.

Thanks Andy!