Heater Core! 85 Ford F-150

So I pulled the heater core out and headed to the store to get another one for my F-150, straight 6, with an air conditioning system that hasn’t been hooked up for over 10 years. I tried the four major stores down here, Advance AutoParts, O’Reiley’s, AutoZone, and Napa. Nobody has it. They all have the block style one that looks like a big rectangle. The plastic housing unit will not allow that one to fit (after trying to make it fit for about ten minutes before realizing it was hitting the housing mold that is holding some kind of cable to it). What gives? Where can I get a heater core that actually will go in my truck? Salvage yard? Dealer?

When I run into this situation where nobody has the part, here’s where I go. http://www.rockauto.com/

They haven’t failed me yet!

Tester

I checked out the site. The two actual pictures won’t work but the sketched one might. I am going to check locally first and use this as my third option, or maybe my second if the dealer can’t get it done. I need to look at the return policy in case it will not work. Thanks for the information and I will be sure to bookmark the site.