New 6 Lug wheels on Old 6 lug trucks

[sir_talk_alot]

im sure this topic has been covered, unfortunately every search i did on google, i couldnt find the right info. im not looking at using new oem wheels, i want to use aftermarket. im looking at a set of american racing 20" wheels, newer 6 lug chevy pattern, will they fit on my 1970 c-10 6 lug truck? and will i need wheel spacers or will they bolt on? what wheel sizes can i run that will work. thanks, im appreciative and im sure others are too.