Im looking at buing some c6 wheels for my 99 trans am. What would i need to mount these wheels? These are the wheel specs: 18/8.5" 56mm Front, 19/10 79mm Rear

 

I have 18x9.5 in the front and 18x10.5 in the rear , they fit fine.

 

Yes, well his question wasnt about wheels that size.
Those wheels seem to be OEM C6 wheels, which will not fit directly onto an f-body. The fronts should be fine, but the rears will need a larger spacer/adapter. 1" minimum.
Honestly, I hate staggered wheels, especially on an f-body. Stick with 18 all around.
My old car:

 

I had to get 1.25" wheel adapters for the rear on mine. 5x4.75-5x4.75

 

You'll need 1.25" spacers on the rear!!! and on the front i put 1" spacer to make them flush with the fenders...

 

1.25 is the correct size for the rear. Fronts will fit without issue.

 

Thanks for all the info it was very helpful

 

I have a set of C6 wheels for sale. I only want $400 for the set. They dont have tires on them. Minor curb rash. Let me know if your interested and i'll send you some pix.

 

PM sent

 

Good luck!

 

I did exactly the same thing. I put them on without the spacers. looked goofy.
Now i have the adapters works perfect.

 

I have C6 Z06s on my car with no spacers. It does look slightly funny in the rear, but I plan on selling them soon so I haven't gone out and bought a spacer for the rear.

 

Those offsets are designed for the corvette & not the fbody.
If one stays in the 38mm-- 53 mm offset you are safe providing you use the right size tire.

 

Ok so i bought the wheels and tires. I dont have any idea what kind of spacers to buy. what is a good brand?

 

Did you put on a spacer at all?? Do you have pics with them on your car?

 

that red and black car look sick.. good job..

 

Whats a good brand of wheel adapters

 

Same wheels i want to put on my car what size tires did you put on those 18's there michael?

 

Those OEM C6 wheels look sick on your old car. I was just curious what size they were. I have a 95 trans am and I want to go with 18's all around but not sure about the width. Don't want any rubbing!

 

Hate staggered wheels on a f body lol, ive heard it all now