Open Discussion on Suspension Options

[My427stang]

I think softer springs are going to compound it.  I would recommend a stiffer spring, lower nose if acceptable, and a more firm shock.  Might be able to just get away with a stout shock and no other changes too, or maybe limiting straps to keep the nose from coming up too high and changing alignment. 

I run my Mustang at 3.0 degrees Driver / 3.5 Passenger for caster, 1/8 toe and 1/2 a degree camber.  However it does have the upper control arms dropped too, it is rock steady to 140.

May want to see what the wheels do when you jack it up.  The nose could be coming up and changing toe and camber so much that you are riding on the edges. 

[frnkeore]

What kind/type of traction bars are you using?

[Thumperbird]

No bars, I launch at idle and just back off a touch when it wants to break loose, this is only maybe a 12 second car remember, though have not timed it.
Going to look into rolling rear fender lip, that with a little more wheel offset and I should be able to increase tire width 1 to 1.5", around 9" tread now.
I do suspect the front wheel geometry goes to heck, need to get a video of the car.
It is a unibody, long but very rigid, will sit on 3 jack stands and 4th corner sags less than .5 inches.

[frnkeore]

Something as simple as these, should help:

https://www.ebay.com/itm/Lakewood-Universal-Traction-Bars-Ford-Chevy-SB-350-454-Mopar-383-400-440-Ford/362649678668?epid=5017018124&hash=item546f9af34c:g:hZMAAOxyVLNTA8Ll

They keep the spring from raping and give you a even weight transfer. You should notice a little rise at the rear, under acceleration, transfering weight from the body to the axle and increasing tract.

[amdscooter]

I'm not for cutting springs. Know to many folks who have done it ( and probably done it wrong to boot) and it made them miserable. Drop spindles and maybe a fatter sway up front?

[fe-starliner]

+1 on not cutting springs.  I needed some new coil springs for my Starliner some years ago.  I called  Eaton Detroit Spring, Inc., talked to them and they made me a custom set based on factors such as weight, how low I wanted the front, etc.  Best way to go as far as I'm concerned. Price was reasonable, shipping very quick.

https://www.eatondetroitspring.com/coil-springs/

[Riderjeff]

I'm a big fan of Bilstein products, and you can buy them for your Bird from Thunderbird Headquarters:
http://www.tbirdhq.com/pc_product_detail.asp?key=BF7F462AF82545E2807F3273795DCCD4

Do all 4 corners and you should be very happy with the difference.  Of course, make sure your springs are within factory spec, some good suggestions previously on custom springs as well. 

I've put Bilsteins on all my cars, they really transformed my old Jeep XJ Cherokee and restored new car ride to my Mercedes.