Thought I'd throw some pic's out there as this is a learning experience...

Original Pic, 100% stock:

 

In these pics, there are 2" billet aluminum spacers on the rear, and 1" on the front.

I have 1.25" spacers on order for the rear. I think 2" is too much. What do you guys think?

 

I cant see enough of the front to make a decision, but the rear stick out way too far past the fender. I don't like it at all.

 

I think both front and rear stick out too far, what kind of look are you going for?

 

Heh, thanks for you input.

I don't like how some GM products have their wheels inside of the body. I like when the top outer edge of the tire is flush with the outermost part of a body panel. I own a 1999 suburban and have to use spacers to bring the rear wheels out, and also spacers for the front so larger tires would clear the frame/front bumper.
The front wheels on the IROC look flush to me tho...

I think the original IROC rims look solid so I want to keep them even if I have to pay to have the rim width widened to accommodate 275 45 16 drag tires.

 

Been rethinking this rim/tire issue I'm sure all us retro folk have in bringing our older vehicles up to speed with present technology.

I'm considering buying a set of 4 Corvette ZR1 rims from ebay for <$600. 17x11 for the rear and 17x9 for the front. The wheel spacers I presently have may make this possible... Also, 315 35ZR 17 tires can be acquired for <$200 apiece. I'm aiming for traction on the street at a reasonable price and a decent "superstock" look.

The bolt pattern is the same on these C4 ZR1 rims, but what concerns me is that the fitment was meant for 4th Gen 1993-2002 Camaros.

The lug pattern is spec'd @5x120.65, which is compatible with 3rd gen Camaros, but the hub bore on these rims is spec'd at 70mm. Hub bore on third gen is 74mm isn't it?

 

Found a decent thread here on ThirdGen.org about a similar issue.

Most links are dead in there, so I feel obligated to keep this topic alive.

 

After some research here, I'm going with the black Z06 18x10.5 (rear) and 17x9.5 (front) with chrome lugnuts for about $600, no shipping charges. I like the red outline on the black rims. Might make the door IROC lettering red to match. Just the IROC lettering, no pinstriping. I might drill out that center cap to fit an IROC-Z center cap if it's the right dimensions. I'm ordering tonight! Wish me luck.

Tires I'm drooling over are:
Rear: Continental 295 35ZR 18 @$235ea
Front: Continental 275 40ZR 17 @163ea

 

After more research here on swapping in 4th gen rearends, I decided to check ebay to see what was out there. Low and behold, I found this for $375 + shipping! Same gear ratio as my IROC and the larger disc brakes should fit inside the 18" rims. Also, I've always wanted posi since my first '86 LG4 sport coupe camaro (RIP). Now I'll be able to better plant all 190HP.

I also ordered an adjustable panhard bar...

 

Z06 replica Rims are here a week ahead of time from someone on ebay:
18"x10.5" foreground, 17x.9.5" aft

 

Just got pounded by 2" hailstones, weird in NC...
...
Nice and wide, 10.5" rear, 9.5" front.

 

*

 

The center circle of these replica Z06 rims, will be given a black/red lettering IROC-Z center cap. They made the potential for it to fit very nice
example shown with current worn out center caps.

 

Last best original pic of my 1986 IROC Z-28 IMO.
The time has come for it to be reborn. First the body, then the soul.

 

hmm

 

Got the rubber in today from tirerack. Second time I've ordered tires from them. Always arrived 2nd day from Delaware here on the east coast. Very nice!
Mounted and balanced them at the shop. Brought them home and finally got an idea how they will look. Some pics just to get a flavor of the color mix. Now rethinking some former thoughts:
No:
Red pin-striping
IROC-Z lettering
Yes:
black/red IROC-Z center caps
black/red Chevy emblem on front grille to replace current black/silver 'camaro'

 

Now waiting on the 4th Gen 2002 SLP SS Auburn rear unit to be delivered from Colorado.

I'll try to post pics of these rims on the original axle/front with spacers I currently have and these rim/tire combo before the axle swap.

For these replica Corvette rim sizes (18"/17") some research here says no spacers on the rear, but 2" needed on the front.

 

Generally don't like black rims, but I do like them on your grey car. Nice choice.

 

Hi, thanks but I just realized I'm in the wrong topic section here @thirdgen forums!

Dang, my font size was too large and cut off the bottom half of the 'Tech Board' topic list. Sorry!

 

Finally drilled the holes for the red Iroc-Z center caps and got them mounted on the Z06 center caps.

I'm not totally in love with the look of these new rims. If I could've gotten a 17" stock IROC wheel I would've done that for sure. But I had to get those wide tires on there for grip.
I am glad all the info here on these forums is correct.

On the stock axle there's 2" spacers and 295 35ZR 18's.
On the front there's also 2" spacers and 275 40ZR 17's.

These are not the lug nuts I'll be using. Should I go with black or chrome lug nuts?

 

With this new rim and tire setup, you can see almost everything behind the rims at this current state of progress on the right side of the car.

 

The Stock left side: 245 45R 16's on the left side with original rims. 2" spacer for the rear. No spacer for the front.

 

Weight comparison:
NEW:
52lbs: P295 35 ZR18 + rear new rim
49lbs: P275 40 ZR17 + front new rim
OLD:
48lbs: P245 45 R 16 + rear OEM IROC rim
48lbs: P245 45 R 16 + front OEM IROC rim

 

Axle was delivered to my shop today. $161 for shipping from CO to NC in 5 days. Pretty damn good. I might have to get into the business of selling...

I have to get rid of the old stock 2.73 axle.
And the stock 16" rims with tires.

Is anyone potentially interested in purchasing either?

 

good job dude it looks awesome.

I've been thinking about going with a similar setup on mine.

 

Thanks dude!

Been a long slow day at work... Boss let me install my 2002 SS 3.23 Auburn Posi axle with disc brakes I purchased from Ebay last week.

I had some very minor issues I'll bring up later, but for the most part all the info I gleaned from TGO forums was right on! Spohn Adjustable Panhard Bar still needs adjust, but overall I'm liking this setup so far.
Some pics, taken at dusk after I drove it home. Didn't test the posi-traction yet... :

 

Couple night pics:

 

So just a couple minor issues/observations I had while installing the 10 bolt 4th Gen rear diff and the 18x10.5" rear/17x9.5" front wheels. (just occurred to me I did not take a pic of the rear disc setup. Will do that soon)

First off, I was doing the work on a 2 post lift, which lets the front/rear suspension to hang at it's max, i.e. as far as the front and rear shocks extend.
For the rear, with the new differential installed, no spacers were used since these diff's are almost 2" wider than 3rd Gen. With the new wheels installed, the clearance looked real tight towards the front of the well. When the car was lowered and driven onto the 4 post lift, where the car sits as it does on the ground, clearance was tight but there's about 1/2" to spare. I tried to take some pics, but they didn't come out. I'll try again sometime soon. Reminder to self: Do not let air pressure get low!

Now for the front clearance.
Using a 2" spacer, the outer tie rods were just barely rubbing the inside of the rim. It was so close on both sides, that the interference would happen on just part of the rotation. I've read that the recommended front spacers be 2.25" which would be plenty in this case, but that might make the front wheels stick out too far. My solution was to use the 1/8" shims that came with the original rear rims.

Drove home nice. I didn't push cornering because I need to replace the lower front ball joints. I did notice RPM's at 50MPH was at 2000, which was right around what it was before with original wheels and 2.73 rear gears. But taking off (without doing a burnout) in a straight line, I could hear the engine reach upper RPM's noticeably faster in each gear! or maybe it was just what I wanted to hear? Maybe it was the posi working? More tests are needed.

Pic from my cell on the left front wheel interference with the outer tie rod. 2" spacer only.

One of my next goals is to get rid of those 10.5" pathetic rotors in the front and upgrade to 13" C4.