1990 GT Convertible - Very clunky ride!

Subframe connectors should be full length and of quality. One such brand is here:


Install instructions:


I would just do OEM bushings in the front lower control arms. As for the rear I would OEM complete upper control are replacements and OEM replacement bushing for the uppers that install into the rear end. As for the rear lower control arms I would get these or something compatible:

 
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Hi again, does this sway bar look normal size? Wondering if a previous owner removed the stock one and wanted a firmer ride over stock as this one seems big, thank you
 

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Hi again, does this sway bar look normal size? Wondering if a previous owner removed the stock one and wanted a firmer ride over stock as this one seems big, thank you

It's been a minute since I've been under my 87, but it looks close. Have you measured the diameter? Doing so would confirm if it's the original size.
 
Or 1.3125" which confirms the one the OP has on his car is the OEM piece. Just by looking at the sway bar bushings on the frame mounts and what appears to be missing isolators on the top of the end of the sway bar where the sway bar end links are I would say you need all new bushings for the sway bar including new end links and the lower control arms probably need new bushings as well.
 
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Is the ride clunky like clunky noise or rough ride like jarring don't stick your tongue out ?
I'd swap in some new dampers first.
I'm used to a sports car type ride.
Also the sway bar does little for the ride quality just cornering .
 
Thanks all. Its smooth enough on perfect tarmac BUT every tiny imperfection on the road and the car jars heavily like yes, don;t stick your tongue out. Also I notice I can 'feel' via the steering wheel when the road surface changes to poorer quality (so not bumps but if the road surface is 'grainy'/lesser quality its noticebale on the steering wheel).

Have also noticed today the drivers side front tire sticks out about an inch or so more than the passenger side front tire (rear ones are fine). Might this suggest a bent control arm?
 
Take the car to an alignment shop and ask them to go over it. Have them provide an estimate to fix whatever they find and then you can make the decision to do it yourself or have them do it.

Could be the frame is bent, could be the wrong control arm, could be worn out bushings.
 
Does the driver door still have a sticker on it like this:

1742515991020.webp


Look at the middle right side of the sticker. The F0036 is the code for the front springs and the R0042 is the code for the rear springs. If you can get those codes call these guys and see if they have the right ones.

 
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Any suggestions for stock like spring replacements?

One place to shop...

Dunno really, but I'd venture a guess that the Moog springs are probably supposed to be pretty "stockish". And they're listed for GT vert applications!
Front
Rear


Or these.... :D

 
You can try a 4 cylinder one but the handling goes to complete crap. Have you replaced the control arm bushings? IF they are the factory ones then they are over 30 years old and will be in need.

What size tires are on the car?

You may think is sounds weird but when I put subframe connectors (weld in) on my cars the ride got better.
Hi again. The ride is getting there with new bushings all round and dampers. Last thing for me to consider is the sub frame connectors which given mine is a convertible seems sensible. How much of an improvement have you got doing this on the ride quality as much as 50%?
 
I'm gonna jump in here as someone who has owned, driven and abused many convertibles in my life, the two best, well three actually, things to do would be to add sub frame connectors, shock tower brace and a lower K member brace, there is a K member brace on verts but it's a weeney stamped(?) thin wall X and well, it's factory (meaning barley) adequate. The sub frame connectors do the obvious, the shock tower brace ties the shock towers to the cowel and pretty much cures 'cowel shake', this condition occurs when the car goes over things like R&R crossings, washboard roads and the like, the windshield and dash will move side to side, I have experienced this twice when the 'shake' was soo bad it popped the door open.
Do it, you won't regret it.
 
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