I did mine too and used one from a '76 blazer with air conditioning. the blower fan was about twice as wide so it moves a lot more air. As long as I had the box out i decided that i never wanter to have to remove the unit to replace a blower motor again so i traced a larger hole on the firewall to allow the blower to pass completely through the fire wall. Used some thigk foam insualtion and duct seal to seal the gap between the firewall and heater box upon reinstallation. Now i can unscrew the motor and replace it from the engine compartment with out having to take the heater box out. So far it has lasted 10 years but If i ever need to take it out it will be easier...........
"It aint bragging if you can do it!"
1996 YJ-5 400 SB Chevy, Proflow EFI, NV4500 Trans with 6.34 low, Dynatrac HP Dana 60 Rear / Dana 44 front and 4:88 gears Featured in Sport & Utility June 1997.