20" rims Where to buy?

[iamoscar]

I have seen some nice trucks on here with 20" rims. While I am a ways away form finishing i need to purchase the rims to make sure there are no fitment problems. When search I am finding few with the lug pattern I need and size.

I am looking for American Racing Blvd or Hopster. 20" x 8.5. All four rims no stagger.

Do I have to have them custom made or does someone stock them?

I have a 68 swb. It has a 71 disk front and new axles in the rear that are 5x5.
From what gather from the wisdom on here i need 4.5" backspace. Is this correct?

Do I need to order 5x4.75 and run adapters? I have a 5/7 drop.

Thank you for your input and advice.

[JointTech]

i didnt have to worry about backspacing etc but I still got my wheels/tires locally so any fitment issues were their problem. Also I got to see a couple different tires mounted on my wheels before choosing the ones I wanted. Also they aligned it at the same time. They were the same price as any online order especially when you include shipping. free shipping is out there but rare from what I saw.