Hi,
here are some of the things that might interest you on the 41 heater.
Notice that the 46-48 heaters don,t have the little hole in the upper right hand area. Case for the defrost push-pull knob. Only on 41,s.
The defrost hose is only 1-7/8' vs. The 46-48,s that are a full 2"
make sure you purchase a 41 heater control bracket. 41,s have only one hole. 46-48 have two. One for defrost and the other for heat.
The little push-pull knob one finds is susally cracked and will crumble in between ones finger and thumb. I made some on my lathe from soft brass, them painted them to the correct color. If you need one cal me.
If you want to pen-stripe the case like the originals are, consider using some of that penstripe tape they sell.
When switching from defrost to heat, let the blower motor come to a full stop first.
To stop any rattleing from your defrost rod to the case, install a small gromet.
The three plastic door pulls are just made from beige colored plastic. Take a little oooo grade steel wool and one can polish them like new. No need to purchase new ones.
I hope this helps some.
Al