I just installed a SPAL blower for the A/C and a new motor on the defroster blower. If you removed the heater core, you also removed the defroster blower. The motor for the defroster is available for $150 from Buds but someone recently posted a cheaper solution. Although, having used the Buds unit, it could not have been more simple or successful.
The SPAL blower for the A/C was another story. It is larger than the original by just enough to cause some fitting problems. You'll have to drill a couple of screw holes and cut a corner of the assembly's frame for fitment. Then it will take some strength to get it all crammed back in place. Solid installation though.
With mine, I carefully identified the speed control connectors and matched them to the original, and bench tested to be sure. Now that it is installed, the fan speed switch in the under dash unit does not give me low speed. The low speed position gives me medium speed and the other two positions provide, medium, and high as they should.
I searched the web and vintage air sites pretty extensively and did not find an exact replacement for the underdash face or vents. There are some that are close, but not close enough.
Just things to look forward to.