Don't know if this is the right place for this.My truck is a'57 1/2 ton from texas and when i bought it it had a heater out of a chrysler in it Now,i want to put one in,and sitting in my back yard is a scrapper that i picked up for parts on mine.It's also a '57 1/2 ton only canadian.I pulled the heater out of it with no problems,looks to be in great shape,but,my problem is none of the holes will line up without doing some modifications.I think i'll be able to make it fit,i was just surprised that they were so different,just figured the firewalls were all stamped the same way. headscratch