Noticed that the front suspension on my '89 Allante is very similar to older mustangs - strut on top, single-bushing control arm located by an angled strut/radius rod. However, while on the Mustang, the rod trails the control arm, on my Cadillac, it is front-mounted.

Many of the Mustang/Cougar owners have replaced the rubber bushing on the lower control arm with a spherical bearing, and replaced the big rubber radius rod mount with a spherical end-link (see here http://www.globalwest.net/mustang_1964%20-73%20catalog.htm#Adjustable%20strut%20rod%20kits).
(click on "adjustable strut rod kits")

Has anyone tried this or something similar on a Cadillac of this era? Seems like it would improve the precision of the suspension tremendously. Since the engine cradle is still isolated from the unibody, noise might not be too big of an issue.

Don't know if this will post, but here's a link to a pic of the suspension components...http://www.parts.com/schematics/images/mechanical/Mkp040.gif The part labelled "4" is the lower control arm with strut rod.

It sounds good in theory. I would try and get your hands on a stock Wusstang unit and size it up to yours first. Make sure all the thread sizes and and bearings fit up. Although, I'm still not completly sure how that system works. Got any good pics of the allante front end?

Don't have any pics right now, other than the above-referenced drawings. I have a used engine in transit that I plan on rebuilding. Once I do the swap, I'll be able to get lots of pics.

It occurs to me that the torque rod is the primary means through which the force of the drive wheels is transmitted to the chassis. Since the drive wheels are the primary braking wheels, the same rod has to slow the car down. That makes it a pretty important piece of the chassis, and subject to extreme loads. The mustang piece is for front wheels, and while it does have to deal with braking forces, it doesn't have to deal with the stresses of a FWD V8. The mustang piece (since it is behind the wheels) has to deal with compressive braking forces, but never tension. The Allante rod (which is ahead of the wheels) has to deal with both massive tension (under braking) and compression (under acceleration). Not something to tinker with lightly.

After reading through that site a bit more I have a bit of a better grasp on what you're looking at. The end link may be the big PIA out of the deal. They way global west describes the sperical bearing unit makes sense and could generaly take some, if only marginal, stress off the strut rod. Also, Energy Suspension sells poly businings for the control arms of the Allante. So that may be an option you want to look into. Global West seems pretty adament about the precise angle and direction of travle of the end link. Now taking into acount the extra effort the Allane's has to face you may be better off going with poly here as well if an end link could potentionaly fail if angles aren't correct. Plus the end links on the Fords are more designed for caster adjustmens in racing applications. On an average street car it may not be that much of a dramatic effect.