I have the Vintage Air heater in my '31 (I did have a VA air unit in the same place prior) and while they are fairly big, if you do the installation before wiring and gauge set up, you can hide them.





There are two dash vents and a huge floor vent that is like a hurricane when it's on high. I did have to cut the control off and have to manually open that floor vent as with an 'A' you do run out of room to loop a cable real quick.



This is the firewall fitting - a modified 4 hole a/c version:



The way my car firewall is set up, I couldn't install one like Steve has in his DW's car