Tractor Wheelbase

Hi I read in this forum that if you purchase a tractor that was built prior to 2005 it doesn't matter what size the wheelbase is. Does that apply to tractors I want to buy from the US. I am looking at Pete's 379 from 1997 - 2004 and majority in the States have a factory wheelbase on average 250 -260 " So will I be able to bring it across into Canada because no one seems to know at the Canadian border crossing service or RIV or American Border crossing services. They all simply say no it has to conform to the Provincial standard and In my case Alberta. I also understand that the overal length still applies even if the longer wheelbase is allowed. So if I am pulling a 53 foot trailer with a 260 " wheelbase. Would I be allowed to purchase a permit to allow me to run the extended length in AB or BC or Ontario if anyone can help that would be great. And the only reason I am even considering a longer wheelbase is because they are more readily available and majority are in better shape coming out of the States.

Thnx