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1964 Pontiac GTO Convertible. 68 400 motor. Burgandy red + white top. Owned since Mar 2020.
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Discussion Starter · #1 ·
I am currently running 15s (Cragars) on my 64 GTO. I am getting ready to spend some money on new coils and shocks. I would also like to jump up to 17" Cragars.
What is the largest and widest tire I can run (in the back and front) on my 64 goat before I have to worry about tire rubbing?
I really appreciate any/all feedback on this issue. Thanks!
 

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I don't know how much difference between a '64 and '65 but I'm running 15x8 4.5 setback on the back with 275/60/15 drag radials with 3/4" spacers under stock springs on my '65 and it's tight. 15x7 with 215/70 up front with 1" lowering springs and it's close too but never rubbed. American Racing has a good measurement guide for wheels and setbacks. I rushed my decision to get it on the road so I thought 15" was the biggest I could go over the 14", now I wish I had 17" ...maybe someday with some massaging of the rear wells and I want the spacers out as it looks better.
145475
145476
 

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Premium Member
1964 Pontiac GTO Convertible. 68 400 motor. Burgandy red + white top. Owned since Mar 2020.
Joined
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35 Posts
Discussion Starter · #3 ·
Thank you very much, especially the pics. I was initially thinking the biggest tire I could use in back was a 255, but your 275 is almost 1 inch fatter, and 1 inch taller. Once I make all these tire decisions, with Cragars, I will then be shopping for new coil springs and shocks. I think I want the stance to be 1-2 inches above the top of the tires. Any recommendation on whether I should consider coil-over springs? Thank you again for your time and your great pics!
 

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I don't know how much difference between a '64 and '65 but I'm running 15x8 4.5 setback on the back with 275/60/15 drag radials with 3/4" spacers under stock springs on my '65 and it's tight. 15x7 with 215/70 up front with 1" lowering springs and it's close too but never rubbed. American Racing has a good measurement guide for wheels and setbacks. I rushed my decision to get it on the road so I thought 15" was the biggest I could go over the 14", now I wish I had 17" ...maybe someday with some massaging of the rear wells and I want the spacers out as it looks better. View attachment 145475 View attachment 145476
Those meats look killer! Had I not gone the 17", lower profile look this is what I'd have done. Looks mean.

MyPops, I have a '66 and got 17 x 10 with 4.5 backspacing and 275/40 tire on the rear. Had to use a 5mm spacer to prevent inner framerail rub. Seems to be plenty of room left between the tire and inner fenderwell even with a 1" drop. Not sure if a '64 is drastically different or not though.
 

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Thanks! Like I said I rushed to get the car on the road and thought 15's were a big upgrade but being out of the game for 30 years and now going to shows where 17-20" is normal I wish I would have done 17" but you're limited on tire sizes so I'm considering 18". I found some US Mag wheels similar to my American Racing wheels that are available in 18", idk if I could run 17" in front and 18" back and I have to figure out my back spacing. My fronts are close but I guess if I go shorter then I can go wider. And I want to get rid of the 3/4" resr spring spacers because it sits to high in my opinion, but I need to make more room in the well first and that might have to wait until body and paint. A 275/45/18 is almost identical to the tires I have now just need a 9" rim, but a 17" tire would be a 305/45/17 with a 10" rim and almost 12" wide to keep close to 28" tall so I don't add more rpms.
 

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I don't know much about the coil overs but they look like a good system and are adjustable, I have considered it but they're costly plus idk if they would work with my SSM lift bars and anti sway bar.
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Premium Member
1964 Pontiac GTO Convertible. 68 400 motor. Burgandy red + white top. Owned since Mar 2020.
Joined
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35 Posts
Discussion Starter · #7 ·
Those meats look killer! Had I not gone the 17", lower profile look this is what I'd have done. Looks mean.

MyPops, I have a '66 and got 17 x 10 with 4.5 backspacing and 275/40 tire on the rear. Had to use a 5mm spacer to prevent inner framerail rub. Seems to be plenty of room left between the tire and inner fenderwell even with a 1" drop. Not sure if a '64 is drastically different or not though.
Thank you. Great info!
 

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Premium Member
1964 Pontiac GTO Convertible. 68 400 motor. Burgandy red + white top. Owned since Mar 2020.
Joined
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35 Posts
Discussion Starter · #8 ·
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