It would be interesting to actually measure the shrouds to see if there is are differences.
Look here:
https://www.ford-trucks.com/forums/1...surements.html
Maybe the shroud is for a commercial truck or a 6 cylinder engine. It may look the same but, be different.
You may be able to modify it to fit.
http://www.vanpeltsales.com/FH_web/f...48-51specs.htm