I have 18s with 245/45. I got OEM stile struts 3 months latter. And install the Coil Spring Spreaders in before installing the struts. I didn't have to do anything special the the wheels or suspension. There are a few members here riding on that combination.

 

What is the difference with 18's is the bottom spring holder higher so the tire wont hit? I want the back to sit higher

 

The 18s where made for the car so no mods were needed for them to fit. 245/45×18 is an inch wider, but almost the same hight as the stock 16 tires.

https://www.google.com/search?q=rear...23717310363443
Go here to see the Coil Spacers. That's what I used to lift the rear 2".

 

JC...
You used these?

Ive broken sooo many springs using these things...
I will never use them again..

 

This is what was already crammed into my front springs when I bought the 84..LOL They came out first chance i got...LOL believe that!! There were two in each front spring!! It was hideous

 

Yes I never liked those things either...
But for your best way to transfer weight/traction to the rear... IMO ...
90/10 drag shocks... No "wedges" needed!

 

They will be 90/10 in the front and 70/30 in the back. Going on the car soon!!

 

Those will help

 

Yes Dave, they have been in my rear springs for almost 2 years now. I also had this type on my 98 Monte LS and my 86 Firebird. Never had any problems with them. YET! If it wasn't so cold out I would go take a pic so you could see how they are installed. I used 2 per spring, mounting one towards the front and the other towards the rear of the spring. Skipping a coil wind between the 2. I haven't even had any slippage with this configuration. (Knock on Wood) Any other option required welding or some other mod I didn't want to do.

 

Do they rattle or anything? Do they have rubber or anything on the ends?