I would love to see those pics of your dads Bronco. I finally did alittle research today, I didn't realize they made Broncos that long, I was thinking it was the Bronco II that was in the 90's
I just hope I can pull it off.
Thank You edwalsh8. this is becomming unanimous on the wheels

Looks like I have a little gluing to do.
I will get those dimensions this evening after work, I do know these axle should fit almost perfectly, well, sort of.
http://www.rc4wdstore.com/2/product_info.php?cPath=19&products_id=822
http://www.rc4wdstore.com/2/product_info.php?cPath=19&products_id=823
I also found out from a friend in RI, that Venom Mini Giant Axles might work, but that will have to be an ebay thing I believe. I don't thinks its made anymore.
As for the scale, its bigger then 1\24 but smaller then 1\14, Not sure, maybe after I get the dimensions you can tell me