Months ago I bought a new heater core from Autozone -- dashboard is apart so I thought I should replace it.  Well, just started the project today.  Got the heater box out and took it apart and lo and behold the old core has different dims than the new one.   The old one is 2.5" thick and the new one is only 2" thick.   It doesn't seem like this should be a big problem, except for the brackets that hold the core to the box - they don't come close to holding the core tight.  Luckily I found the receipt so I can return the core, but wanted to post on here to see if anyone else has had a similar issue.  The core I took out was not original - it was replaced in 1983 according to the warranty sticker on it.  Maybe it's the wrong size?   Or maybe I should get new brackets for the new core?  If I do get a different one, any thoughts about where I should order from?  

There is one core air conditioned cars and one for non A/C...maybe the problem

|UPDATED|2/25/2012 7:41:39 PM (AZT)|/UPDATED|

Thanks, that could be the problem but I just took it back to Autozone and they checked the PN for with A/C and it's the one they sold me.  I'm wondering if the brackets that I have that are wrong.  The parts guy was telling me it's typical that the brackets should have spring clips in them to take up the slack for different sizes.  Does that sound correct to anyone?

Sounds like a good answer to me!!  I will believe anything until I prove it wrong!!

After some more research, I think the one I bought from Autozone is just plain wrong.  The core for non A/C cars looks totally different.  I took the Autozone one back and ordered one from Napa - should be here tomorrow.  Napa lists the dims on their website and this one looks correct.  I'll confirm after I get it.  

Hey Dave. I own a rad shop. Yes a 76 heater core w/ac is completly different from one wo. They are both 2 1/2 thick but pipes are completely different. The aftermarket number I have is either 2-262 or 39-9081. Hopefully by now you have the right one. If not let me know if I can help. T

Got the dashout do not forget to replace all of the lights.  Now is the time. I have a place that sells lights for a fraction of what the autoparts places can.  They also mail first class and you only pay postage.  

Terry - thanks much.  You confirmed exactly what I suspected.  I didn't make it to Napa after work today, but I'm reasonably confident that it will be the correct 2 1/2" when I pick it up.  

Dang - picked up the Napa core today and it's the same as the Autozone - 2" thick, not 2 1/2"!  I think they're from the same supplier.  Looks like I have two options: 1) order one from one of the 'Vette suppliers (for double the $$ and still no guarantee it's correct) or 2) figure out a way to use the thinner core.  I could get some different brackets or find a way to take up the slack using my existing brackets.  If there were some springs I could stick in there that'd be perfect, but they'd have to be pretty specialized.  Any thoughts?  Thanks, Dave

Hey Dave. I wouldn't use the 2" it won' seal right, besides you shouldn't have to. I will see what I can come up with when I get to work tomorrow. If you want send me a pm with your. Ph. # and I'll give ya a call. T