The blower has a few screws attaching it underneath. Then it drops down from the heater core box, if it is original.

On my truck with a later V8, I have to loosen the box the heater core is in for more wiggle room.

Here are some photos:

04/19/2017 – heater core replacement

Check the captions on the photos.

Also, look for a link to an earlier replacement for more pictures.

Look for a link to Burgies page about this too.

Good luck.