Does anyone sell a replacement that actually fits? I bought one from O'reilly and that didn't work. Then I got a Spectra Pro from Autozone and it doesn't quite fit right, either. The hose lines are slightly too far apart. I can bend them ever so slightly to fit the evaporator box but the top of the tank is taller than the original and the gasket won't fit.

Anyone who has replaced the heater core with an aftermarket unit, how did you do it?

 

Yeah, the new, replacement cores kinda suck as far a fitting goes. There are also two different end tank designs. The original design is still available, I got mine from Rock Auto. On their website you can see what the core looks like. On mine, even though the tank design was like original, the hose nipples were also just a hair further apart.
Instead of spreading the nipples I enlarged the holes in the evaporator case a little bit.
Here is a picture of the two different end tanks. The original style is on the right.

 

I know I sound like a broken record, but...NAPA. I've never had a problem with fitting a heater core I got there. I replaced the core in my '79 a couple of years ago, and the replacement was identical to the one I pulled out.

 

The only thing on NAPA's site is the same Spectra Premium I got from Autozone.

 

It's been a couple of years. Maybe they've changed their product line since then. I hope not...

 

just got finished doing mine today. I bought mine from Napa, fittings were a little farther apart. I used my air cut off saw and made the hole a little bigger, you can't tell.

I also had a problem trying to find a replacement fan, I could only find a non A/C one. I ended sandblasting mine this am and gave it a coat of paint.

 

Were you able to use the original gasket?

 

I did use the original. It didn't fit perfect, but not too bad. The top right corner was tight, had to swear a little.

 

Throw that aluminum pile of crap in the garbage and get this:

Laurel Mountain Mustang - 1965-1966 (ALL) & 1967-1968 (W/O AIR) MUSTANG HEATER CORE BRASS

It's a perfect fit, OE gasket and all. I put one of these in my Supercab build. If you plan to order one from them make sure to tell them you want brass or they will send you an aluminum as well.



A couple years ago everyone was still producing the OE brass core. They seem to all switched over to the Spectra brand.

If any one plans on keeping their truck for a while I'd highly advise getting a spare. I suspect that the bass will eventually become history. I've got 2 new brass cores for future use.