Not sure what you have, but down here a 51 Chevy big truck has 5 lug front hubs and 10 lug rears, same wheels front and rear, all on 7.25" bolt circle.
But down here the largest 51 Chevy is only a 2 ton...
Don't know what bolt pattern a 51 Chevy "3 ton" in Canada has?
I have sent my email to you so you can pass along a picture.
Grigg