Greg aka South Side Goons & Hitmen, wrote several responses to my questions. Greg, Thank You Very Much, I really appreciate it.
That's what I was afraid of (you had either 3 1/2 inch backpsacing or 3.75").
There are only 2 ways to go about fixing the rubbing problem of the P235/60R15's on your 1968.
The wheel backspacing should be increased to about 4.25". Or go with P 215/60R15 on the front. Right now you have a slightly negative offset.
In plain English, that means replace you will need to replace the front wheels or go with P215/60R15's on the front...The P215/60R15 is right about what the metric equivalent of a E60x15 is..... Please keep in mind some tire manufacturer's have wider footprint's than others even if you compare 2 exact same sizes by different manufacturers you may find one tire is noticeably wider than the other.
Don't just take my word for it. I worked in the auto service industry from 1989-1998. But, I went from 1998-2006 without caring about any of this stuff until I bought another Camaro last year, which was 12 years after I sold all my Camaro's. That means I am shaking off alot of rust the past 12 months.
Ok here is the deal. Check out this link. It will help explain what I am talking about. https://www.rsracing.com/tech-wheel.html#backspace
Then check out this one and scroll through the 15 photo's. http://www.carcraft.com/techarticles.../photo_06.html
I would definitely not just take my word for it. I encourage you to seek the advice of a professional at a tire shop near your home or work. It's not that I don't know what I am talking about. I feel that I do. But I have been out of the game since 1998. Nonetheless this was my specialty even when I worked at new car dealers or Goodyear, Firestone, Kelly tires etc. I worked at the service counter mostly as an assistant service manager or service advisor. That means what I am telling you another shop may confirm. Feel free to copy & paste this anywhere you want or in any forum you want to get a second opinion.
The SSG&H Bottom Line: You will either need to go to a smaller front tire or increase the offset/backspacing on the front wheels which means the current wheels would have to be replaced.
Please feel free to respond if you have any questions!
SSG&H aka Greg
The Backspacing is 3 1/2 inches and the disc brake conversion is already installed.
I believe the backspacing on the OEM Torq Thrust wheels was less than that of the Rally's. I think Rally's were 15x7 w/ 4.25" backspacing. Some Torq Thrust wheels like this one here were less http://cgi.ebay.com/ebaymotors/15X7-...QQcmdZViewItem
From what I understand, is that on 1967-1968 Camaro's, you can get more tire on the back of the '67's & 68's cars than you can on a 1969 Camaro. However on a 1969 Camaro you can get more tire on the front of the car than you will be able to on a 1968 or 1967.
If I am not mistaken the 1968 Z28 had either E70-15 or E60-15. This equates to around P215/60R15. Bias ply tires also have more of a square shoulder where as radials have a more rounded shoulder to improve handling & cornering. But the rounded shoulder also will cause tire rub as it increases the contact patch which is known as the footprint of the tire.
Here are 2 helpful links. http://www.turbinecar.com/tires.htm
Drag your mouse over the photos to see how skinny the tires were on these cars.
1) You said 1/2" backspacing Did you mean 4 1/2" or 3 1/2"?
2) Did you put the disc brakes on the car as of yet or does it still have the drums on there?
---Quote (Originally by Camaros-n-Chevelles)---
I have a 68 Camaro that was originally a Drum Brake Car. I purchased a Disc Brake Conversion Kit. I did not go with the Drop Spindles since I wanted to keep the rise height unchanged. It was originally a 327 A/C Car, but now has a 383 in its place. The A/C is installed with the exception of the compressor. As far as the backspacing, the American Racing Torq Thrust Rims are early rims made in the late 70s or early 80s. There was a 1/2 on the back of the rim if that helps.
Thanks A Million for your help.