Upgrade Heater Fan???

I've seen instructions for upgrading CJ heater fans using a chevy fan and some minor cutting. Is there a similar upgrade available for an XJ?? My 87 XJ heater seems to be pretty weak compared to other vehicles I've owned and would like to get more air moving through those vents. Thanks.

I looked but have not found anything. The CJ/YJ motor is very different. I did replace my motor though with a new one and am getting about 50% more air flow. I believe the old one was tired and getting weak or perhaps the bushings were causing too much drag. Either way its not bad now. Maybe pull the old one out and check it over. While its out check the inside of the box for debries that may reduce airflow