Heater Core replacement - '67 A Body

Hello A Team!

I've got my heater core bypassed (BEFORE it dumped coolant inside the car), in anticipation of replacing it. Research tells me that the replacement heater cores don't always match up cleanly. Has anyone swapped one recently enough to be able to comment on a part number or source for the right fit? These cores show up as matches. This car does not have A/C.

ProRad APDI 9010073
Spectra (or Murray, same part number through O'Reilly) 94503

I know this is a fairly big job involving pulling the dash, possibly the console, etc... First time for me on that, so this topic is named generically. I have a feeling that I'll be back for more!

Thanks in advance!

I purchased one of these off of eBay from AUTOZONE. It fit perfectly for me on my '67 Barracuda and was $37.99 with free shipping.

http://www.ebay.com/itm/HVAC-Heater...Parts_Accessories&hash=item3f480709b5&vxp=mtr