wheel fitment: '83 to '03?

[D.H.]

i currently have nice aluminum 8 lug wheels on my 1983 3/4 ton C20 Scottsdale (Silverado light).
i need to know if they will fit and work ok on my new-to-me 2003 Silverado 2500HD 4x4?

also, how wide can i go on tires on stock width (16x6"?) wheels?

thanks

dave