My favorite aspect to work on in a car is the handling. You can have all the power on the world, but if you can't use it, does it really exist?Of the first generation Mustangs, ours were the most refined and capable. It has a longer wheelbase, wider track and improved suspension geometry that eliminates the need for the upper control arm drop to correct camber change. With this in mind, you could save a lot of money and greatly improve the handling by just addressing the shortcomings that remain.
The first major thing to address is the strut rod and it's spongy bushing. Of the different designs I looked at, I liked Street Or Track the best because of what I see as stronger design. By upgrading the strut rod, your turning, acceleration and braking will improve dramatically because you no longer have to wait for it big bushing to compress and rebound. Also, Street or Track actually races with their parts.
The next step would be to replace the unreliable eccentric bolt with camber lockout plates. If you are looking to fly through the twisties, you don't want anything to move and change your suspension geometry. It's a little more work to align, but we'll worth it for performance and safety.
Next, unless you are competitively racing on a road course, I would recommend using stock upper and lower control arms. Uppers you can leave a they come out of the box. Lowers, I would box with a reinforcement plate welded to the bottom. You can even make your own out of 14 gauge mild steel. This addresses the lack of stiffness and the tendency for them to crack, and sometimes completely break at the bend they have to clear the frame while going through it's travel. If you ever watched the end of the chase in Bullitt, you will see what I mean.
Another inexpensive improvement with dramatic results are traction bars. Like the solid strut rod, it controls movement under acceleration AND braking. In this case, the vertical rotation of the rear end that causes spring wind up. Traction masters is what I used. I mounted them directly to the next thing I recommend.
Subframe connectors. I used tin man subframes because they are rectangular, they match the existing from frame rail and hug the for pans. You can have the best suspension parts in the world but that force will go somewhere. In this case, it will flex the 50 year old chassis, which might even be enough to cancel out your other improvements.
The last few, self explanatory pieces, 1 1/8 front sway bar with polyurethane bushings. Total control rear sway bar. The last, quality hydraulic shocks. I recommend QA1 non adjustable. If you are going to track it on a road course or autocross, Viking double adjustable along with 620 lb front coils and 193 lb 5 leaf rear springs.
My post was long winded, but I love a good handling car. It just doesn't take thousands and thousands of dollars to do it on our cars. I've put time and money to experiment and this is what I found I like and does well on the street while putting a smile on your face and turning heads at the track.
