I have a 82 Fulsize Chev stepside
front-3" Bell Tech spindles/bag setup
rear-Ford 9" rear end,bridge,parrell 4-link/bags

What width,tire size/Back spacing should I go with to run 20's

MAC

Seriously, the rear isn't an off-the-shelf measurement now that it has a Ford 9inch.

For the front, a 20x8 will work nicely with 4.5" backspace, or 20x8.5" with a 5" backspace.

Again, the rear you will need to measure for proper backspace, unless the replacement Ford 9inch is the same exact width (drum-to-drum) as the OE GM 10bolt.

As for tires, it depends how big you want to go, how much you have cut and whether you want to lay frame.

255/35/20 front and 285/30/20 rear
245/40/20 front and 275/35/20 rear
255/45/20 front and 295/40/20 rear
245/40/20 front and 295/40/20 rear
255/50/20 front and 305/40/20 rear
265/50/20 front and 295/45/20 rear
265/50/20 front and 275/55/20 rear*hehe you might see this on my gmc............... maybe.

My Ford 9" is 7/8" wider drum-drum than the stock 12 bolt.The trucks got a really healthy motor(500+hp) in it so I want a little more rubber in the rear.8.5"-9.0" rim with 305/40/20??? I want it to be low but it doesn't have to lay frame. Do you guys have any pics of a stepside with this done to it?