315...grind the IRS bolt?
 

If you go with the 10.5" rim its suggested to grind the bolt or you could buy the ones from americanmuscle.com. Running the 315's on the stock 9 inch is not recommended, but is it "bad"? If i wanted to run the nitto 315 drag radials on the 9 inch rim do i still need to watch out for the IRS bolt? Need some help here please...maybe a picture or two would make it a lil more clear.

kept searching...found a few more things that confused me...
I'm definitely going with the nitto 315's..BUT..i read if you go with the 3/8 spacer that will "help" with clearance. Would i still need to grind/replace the IRS bolt? Anybody running a 315 out back on a cobra that can help me out? I also read differant cars will have differant clearance with the same mods.

315 on a 9" rim is not the way to go. Max even I would do is 305 nittos because they run small and people do go that way on the rear. Me I would just replace the bolts and run the 10.5" rim with 315's.

Running 315's on a 9" rim is completely pointless. You wont get the right contact patch from the tire.

x10000!!

With MM 1/4 inch spacer (49.99) you won't need to grind the IRS bolt.Also MM makes a low profile bolt to replace the stock IRS bolt that is very cheap ($9.99) and makes more since than grinding it.

Mine was lowered low enough that I did'nt need either for it to clear the bolt but it was damn close,and I was running BFG DR's that are alot bigger than Nitto's.The 1/4 inch spacer worked perfect.I also ordered the MM bolts but never used them.If I still had them I would let you have them.

Please don't go with a 9 inch rim on the rear with 315's!

ok so im going with 17X8 up front with a 245 or 255...and the rear im going with a 17X10 with 315. I have a 2003 cobra now and it has the eibach lowering springs. Still suggest swapping out the IRS bolt? Or just go with a 305 tire instead? would the 305 make a little more clearance?

305 is probably a more appropriate tire for a ten inch wide rim. I have a set of 18x10" rims that I run 295s on and they slightly bulge.

ok my time being deployed is wearing down. Before i get home im buying the 03/04 replica wheels. 17X9 and 17X10.5 with a 315 in the rear. Nittos run with a 11.75 contact patch...SO...i have been reading and searching on this and would like some input on it.

My cobra has the eibach sport springs installed, so running the 10.5" rim would not need the wheel spacers. Also i am ordering the button head IRS bolt. From what i am seeing thats the perfect combo to run the 315 nittos out back. Is there anyone else running that combo on a 03/04 IRS?

When swapping the IRS bolts do you need to be 'ready' for some snap back once that bolt comes out? Should i have a jackstand under the suspension? Does anyone have pics of the install they did?

anybody...?

You might have better luck over on svtperformance. Not many cobras on here.

315's with IRS bolt and you will be fine.

OK, well thats the setup ill have. I'm about to order the rims/tires and have it waiting for me at home. Random question...do wheel spacers have a hp limit to them?

No need to worry about a limit on those cause they are so small for what you need.

lance how low was your drop? and you said you had spacers too right? Your fender didnt rub the tire?