I have searched this forum, but have found nothing specific enough, so I thought maybe you guys could help me out.

I am going to be lowering it from stock 1" with some umi springs.

I have purchased a set of 17"
http://www.summitracing.com/parts/rce-92-510254dsd

With 6.875 back spacing. My local speed shop told me this is what I needed.

Now I need tires. Wow, what a pain. I didn't realize 17" rims would be such a hard size to find the right tires for.

I would LIKE something a little bigger than a xxx/40/17 Those are proving to be hard to find.

I am looking for any tire size suggestions you have. I would like to put the widest back and front tire on as possible without causing any more headache than it already has. Thank you guys for your time.

EDIT: Forgot to add Widths. 9.5" in the back 7" on the front.

Hi,
What is the width of the rear rims?
I do Believe that 6.875" backspacing might be too much and cause tire rub on the frame and/or exhaust system.
/rgds
Mikael

Yep, just coming back because I realized I forgot that part. 9.5" wheel in the back 7" in the front.

Ok.
With 275/40 or 275/45 tires I would say it will be very close to the frame. To the inside of the fender lip you will have a little more than 2".
I would say a back spacing of 5.25 to 5.5 inches would be optimal. Have measured on my own 69 to verify my answer but maybe someone else has the same setup.
/rgds
Mikael

Those back spaces are meant more for a late Fox body stang or F body Camaro. Way too much back space. You will probably need a spacer/adapter.

17X9.5 on the rear, assuming stock rearend, and you are probably looking at about 5.5" BS to center the tire, side-to-side...

Yeah, those backspaces are way off. You should be looking for wheels with zero offset, or near zero offset. 275/40 is good for a 9.5" width, 245/40 might be a little wide for a 7" width.

Ok, thanks for the info guys. I will see what I can do.

So ya...you guys were right. Luckily the guys at the speed shop are nice people. They ordered me a new set with a 5.25 backspace.

Now, is anyone 100% on the widest tallest tire I can fit in the back without any issues on a set of 1" lowering springs ?

I'm thinking a 285/40-17 in regular tires. (~26" tall)
275/50-17 in a Drag Radial. (~28" tall)

Awesome info, thank you!