65 Chevelle backspacing

[65 drop top]

Looking to run 18/19x8 front and 20x8.5 rear wheels on my 65 Chevelle. What's the right backspacing?

[65 drop top]

Still looking for sizing info, any help is appreciated. Thanks

[65SSZ06]

I have Hotchkiss upper control arms on my 65 and have run 255/40/18 on 9" with 6" backspace in the front and 275/35/18 rears. Had to run a 3/8 spacer in the front and extend the bump stops too. Really 5 3/4" on 8" is good in front and a 9 1/2 with 6 1/4 to 6 1/2 should've right on. I've used a 2002 Camaro in wheel fitment guides if you are looking for off the shelf.

[1989GTA]

On my 1965 Buick Skylark I am currently running 5" backspacing on the front and should have gone 5.25". Wheels are 8 x 17 with Nitto 245/45ZR17. I have front disc brakes. On the rear I am running 6.375" backspacing with disc brakes and a 1971 ten-bolt which is 1/2 inch wider per side versus the 65 model. Wheels are 9.5" x 17" with Nitto 285/40ZR17. Hope this is of some help.

[65 drop top]

I'm surprised to hear you guys are fitting a 9 1/2 wheel in the rear. I was thinking a 8 1/2 with a 275/35/20 was gonna be as big as I could go.