'70 Challenger Heater Box

[340Challman]

Hey All,

In doing the restoration of my heater box I have noticed the fit and finish of the fiberglass housings leaves a lot to be desired. Especially the two halves with the heater core inside. Warping, twisting and just plain dimensional differences. Thinking that I could prevent air from escaping at unwanted locations is absolutely comical. The poor fit has caused the clamping areas to have broken off years ago so I can only get 4 of the 8 spring clamps back on. It is pretty horrendous. Is this poor fit normal? If it is, I don't suppose there is much point in trying to source better ones is there? What have you all experienced and how did you get around it?
I guess I should mention it is a non-A/C car.
Thanks.

[ec_co]

I have no clue about the fit and finish, but this reproduction heater box might be an option

https://www.classicindustries.com/product/me1654.html

[340Challman]

I have no clue about the fit and finish, but this reproduction heater box might be an option

https://www.classicindustries.com/product/me1654.html

Yeah, I definitely looked at that. Unfortunately my broken clamp areas are on the other piece, so I wouldn't gain anything from the clamping standpoint. It may fit better and maybe that's my only option.

Have you had yours apart? Was the fit bad? If I'm just unlucky to have a poorly fitting set, I'd consider trying to round up others. If they're all bad, there doesn't seem to be much point. Other than maybe the clamping areas wouldn't be all broken.

[ec_co]

Rebuilding my heater box was the very first thing I restored about 10 years ago. No problems with mine at all, no warping, no cracking and the pieces went back together just fine.

Do you have the broken pieces? If so, you might want to try plastic welding it with a hot stapler and melting iron

[Duodec]

I'm finally rebuilding my '71 A/C box, which screwed together.  The housing was in great shape, and test fitting it after cleanup and air door and actuator reinstallations went well. 

My biggest problem was finding a new heater core that actually fit.  Three different aftermarket units had issues that would have required modifying the A/C box.  I ended up sending my OEM core to Glen Ray to get it rebuilt (and it fits perfectly). 

I also test fit an aftermarket evaporator and same thing.  It did not fit and would have required significant tweaking, and the refrigerant pipes would have come out at an angle instead of straight (which could cause issues with the hose/tube connections; there isn't a lot flexibility there).  Fortunately the factory unit is still in working condition.  I leak tested and flushed it out and its going back into the box. 

[1970Cuda]

So I completed my heater box rebuild and it turned out great. At least as good as I think possible, given the original design. The original thermal plastic with sisal fiber added for strength is fairly rigid, especially compared to the reproduction box cover, which is plastic. The front reproduction cover is flimsy to say the least. I used my original housing, and had my core rebuilt by Glen-Ray Radiators. (Use that if possible as the reproductions are inferior.)

Also, if you are going to rebuild the original box, use the Detroit Muscle rebuild kit; it has competent instructions on how to restore the box. Use the original clips too, because the repops aren't exactly the same. And have the blower motor rebuilt too (IMO) to ensure it's in proper working condition.

What I found that really helped the look (and was recommended) was to clean the box thoroughly (without messing up the date code) and then shoot matte clear on it. You can see my build on this site.

You can see https://forum.e-bodies.org/your-restoration-project-roseville-moparts/10/1970-fe5-cuda-build/200/120. Page 8.

But if you decide to just pass, you can always install it for "show" and not have a functional heater box, since most people won't drive their restorations during the Winter months anyway. Good luck on rebuilding your heater box.

[340Challman]

So it sounds like I must have poor pieces. As I said, 4 of the 8 clamping areas are broken to the point that the clamps just fall off. There is nothing there for them to grab onto. It has been like that since I bought it. That is most likely from the strain that they were under because of the poor fit. The rest of the heater box assembly is fully restored. I just have 1/8 inch gaps in multiple locations around the perimeter in addition to misalignment issues. Maybe I will install it and start looking for a different one. I don't want to hold up the assembly of my car just because of the heater.
Thanks guys.

[Dakota]

I'm late to the party on proving a reply, but I didn't have issues with sealing the 2 halves of my heater box after pulling it apart.

[RUNCHARGER]

I've heard of quality issues with the repro heater boxes but not with original pieces. It is getting hard to find nice original boxes though.

[340Challman]

I've heard of quality issues with the repro heater boxes but not with original pieces. It is getting hard to find nice original boxes though.

It's always nice to be the one setting the bad end of the spectrum.
Oh well, I'll just start looking for some different pieces. Right now I want to get this thing together and drive it.