[Droptop64]

I know there has been much discussion on this site concerning poly suspension components versus rubber, going to larger wheel sizes and the degradation in ride quality concerning those two items.
I can relay my own experience and hopefully this will help someone looking to do what I recently did.
I bought a restored '64 GTO convertible in October, 2004. The previous owner did everything except for the suspension, which was original and in fair condition with the exception of the rear control arms which were falling apart quickly. I wanted to make the car a driver, and decided to only change things that could easily be unbolted and returned to stock.
After a lot of research on this site, I decided to go with a full front end rebuild kit with polygraphite bushings from P-S-T, a 1 1/4" swaybar and Hotchkiss 1" lowered springs. For the rear, all rubber bushed, boxed arms from Ames. The rear boxed lower arms were part of a kit that included a 1" sway bar, where my car had none. I re-used the rear coils, and the shocks that came with the car since they both seemed to be in good condition. I think the shocks are NAPA, they are red in color.
For tires and wheels, I went with 4 - 16x8 TorquethrustII's. Tire sizes are 205/55x16, and 235/60x16. This gave me roughly the same tread width front and rear with the rear being about 1/2' wider, a tire that was 27.1" tall in the rear, and the front tires being shorter ( 25" tall) gave the stance a slight rake. To make the front fender well settle over the new tires better, I took an additional 1/2 coil out of the Hotchkiss springs.
Ride quality is excellent. Keep in mind this is a convertible that had polyester red-line gumby tires on it. All of the float and door handle cornering is gone. This car corners totally flat, goes exactly where you point it immediately, and rides very comfortably. The only minor difference in ride quality is that something like tar strips will now show up with the slightest increase in "sharpness of impact". Very slight increase. I can equate the ride to my wife's 2004 3 series BMW with the sport package in that respect, and much smoother than that in all others. Oh, and the squeaking from the front poly bushings?? Not there.

[Droptop64]

I know there has been much discussion on this site concerning poly suspension components versus rubber, going to larger wheel sizes and the degradation in ride quality concerning those two items.
I can relay my own experience and hopefully this will help someone looking to do what I recently did.
I bought a restored '64 GTO convertible in October, 2004. The previous owner did everything except for the suspension, which was original and in fair condition with the exception of the rear control arms which were falling apart quickly. I wanted to make the car a driver, and decided to only change things that could easily be unbolted and returned to stock.
After a lot of research on this site, I decided to go with a full front end rebuild kit with polygraphite bushings from P-S-T, a 1 1/4" swaybar and Hotchkiss 1" lowered springs. For the rear, all rubber bushed, boxed arms from Ames. The rear boxed lower arms were part of a kit that included a 1" sway bar, where my car had none. I re-used the rear coils, and the shocks that came with the car since they both seemed to be in good condition. I think the shocks are NAPA, they are red in color.
For tires and wheels, I went with 4 - 16x8 TorquethrustII's. Tire sizes are 205/55x16, and 235/60x16. This gave me roughly the same tread width front and rear with the rear being about 1/2' wider, a tire that was 27.1" tall in the rear, and the front tires being shorter ( 25" tall) gave the stance a slight rake. To make the front fender well settle over the new tires better, I took an additional 1/2 coil out of the Hotchkiss springs.
Ride quality is excellent. Keep in mind this is a convertible that had polyester red-line gumby tires on it. All of the float and door handle cornering is gone. This car corners totally flat, goes exactly where you point it immediately, and rides very comfortably. The only minor difference in ride quality is that something like tar strips will now show up with the slightest increase in "sharpness of impact". Very slight increase. I can equate the ride to my wife's 2004 3 series BMW with the sport package in that respect, and much smoother than that in all others. Oh, and the squeaking from the front poly bushings?? Not there.

[Mike P.]

Mike D.

Congrats on the '64 GTO. I'll keep an eye out for you. I'm in Fairfax, Red '68 Firebird Convertible.

Mike P.

[gtoformula]

The increase in abrupt bump harshness is probably due more to tires than the poly bushings. Going to a lower profile sidewall (less meat between the rim and the tire tread) will amplify bump harshness.

[Droptop64]

"The increase in abrupt bump harshness is probably due more to tires than the poly bushings. Going to a lower profile sidewall (less meat between the rim and the tire tread) will amplify bump harshness."

That and the fact that I'm running 40 PSI in the front, 35 in the rear, where it used to be 28 all around. All in all, it's changed the car totally, and it's a blast to drive.