On my 70 the resistor for low and medium is attached to the outside of the heater box. And then there's a straight through for high speed. The simple thing was to use the relay to power the straight thru since I never use the massively slower speeds.
You use the wire from the switch to that...
On my 70 I put in a new motor, rebuilt the box, and ran a relay to power the high speed. The relay was by far the thing that most improved the flow, but it still sucks.
The vintage air in my charger with it's newer fan and design flows a lot more
I'm pretty sure I used super glue on mine a couple times!
I bought a used metal replacement style one years ago, cleaned it up and it's been living with the turbo heat ever since.
Will be interesting to see if there's any difference. I've had some 66-70 b body ac/heat boxes (6 or so) at one time in the shop looking at them. Some had more metal in the casing, others more plastic but they were all the exact dimensions as far as I could tell.
I don't remember the eBay name I bought from but my stuff looked like all the stuff the other guys have ended up with. I may have had a reseller intermediary in my way, but there are not a multitude of people making these
I bought mine (ac and heater core) years ago on eBay yes. And I did talk to them and returned the ac. Like David, I found the heater core to be closer but found a gray beard to fix my replacement circa 1999 unit. I kept the heater core because it looked like it could be adapted to fit if needed...
You're out ahead of your skis my friend.
I've met Ayilar in person multiple times and plan to collaborate with him on next year's cattle drive.
He and I have no beef. I simply pointed out a strange amount of positivity towards a vendor who keeps messing this stuff up.
I appreciate all sorts...