Is there a sudden shortage of replacement heater cores? I know....that was a sarcastic comment. As far as I know, there are plenty of aftermarket and GM replacements still out there. I recently bought a GM unit and installed in my car. Not a fun job but easier with the pass seat removed. And yes, some of those screws are hard to get to but very doable.I've searched here and Googled around and been unable to find any useful pictures of the area around the heater core and thought I would help out by posting some up.
There is one hidden 7/32" screw holding the heater core lower box on to the upper part in the back, almost against the firewall. You can not see this one, it is up on the back side.
I followed Qalo's SS handbook to get this far. I'm thinking I'll try to find a bar and plate type fluid cooler to use as a heater core, if I can find one around the correct dimensions. It appears that the core can be slightly larger than the stock piece if you are willing to trim the box around it. This opens up the choices for cheap oil coolers since almost none are as small as the stock core. Maybe 11" x 7.5" x 2"?
I’m hoping I can remove some of the ribbing from this area to gain the space needed for a more robust solution. I’m planning on removing the restrictor tee and I’ve read that it is there to prevent damage to the core at higher RPMs and don’t want to have to fix anything again.
While what you are attempting to do should be commended, I would again ask....WHY? I could see doing this if replacement parts were not available and you needed to get creative. Just seems like a lot of work and possibly messing up other functions of the system if not designed or modified properly and what are you really gaining by doing this? In addition to the core/cooler fitting the plastic air box correctly, you will also need to fabricate some sort of fittings to come through the FIrewall for the heater hoses.
As far as I know, the real problems with stock heater cores are they become clogged and don't provide heat. The other issue is they can develop leaks and need replacement. I would most likely not even bother repairing the core since other areas of the HC could be compromised and its a pain to replace, so I would just throw a new part in there. Not to mention, there just aren't as many radiator repair shops in my area as there used to be back in the day. Replacement parts are just more cost effective...IMHO