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Originally Posted by aussiebj  Well after thinking about it after the sale of my fastback ..i picked up a 65 coupe setup like the old transam cars of the 60`s ..it has a 351 cleveland toploader box and a 9 inch out back with a locker in it ..it also has 4 piston disc brakes up front with 2 1/5 inch drum setup out back ,it has the shelby drop up front with koni shocks all round as well as an adjustable panard rod.. big fender fares to cover 15 x 8.5 up front and 15x 10`s out back ....all this for 4k..i love it cant wait to get it to the track http://i158.photobucket.com/albums/t...dthedrside.jpg http://i158.photobucket.com/albums/t...edpassside.jpg |
Hi aussiebj,
I've done two vintage Mustangs ('66 fastback & '69 Boss 302) and limited my suspension, chassis and brake upgrades to mostly period correct changes. About the worst thing about these early Mustangs on a road course was the stock suspension geometry and brakes.
Improving the front suspension is simple stuff and there is not much that you need to change. The biggest improvement to be found is relocating the front upper control arms 1" to 1.5" lower. This is a MAJOR improvement in geometry which allows you to use much less static camber and still keep the front tire contact patch optimal for cornering and more importantly braking! Additionally this change raises the front roll center height which also helps the tire contact patch by reducing tire sidewall rollover.
To help the chassis actually work with firmer springs you also need to triangulate the front subframe, improving the front subframe stiffness is also a big handling boost. Both of these things are easy to do with stiffening done by using factory Monte Carlo bar or the pricier but very good TCI kits.
What spring rates you use will depend on if it the car will be a street car or a race car. Original 1965/66 Shelby street cars used 625lb. front springs and a rear leaf spring with an extra leaf and bolted-on or welded- on control arms. This is adequate but the truth is that no matter what you do with the mounts for the rear leaf springs the rear axle is going to move a round a LOT under hard cornering and this is VERY noticable even on modern high performance street tires. To get the ass end to work its best you need to install a Watt's link and make sure it can be adjusted for roll center height for a race application.
Some folks will tell you to go with a Panhard bar setup but a Panhard bar is a serious compromise on a leaf spring rear axle. The problem is made even worse if the axle also has the extra control arms installed on the rear axle. Think about what a Panhard bar is doing with the axle as it travels through its arc and you will see the axle must move side to side slightly as the axle moves up and down. This causes the rear springs to bind as the axle moves up and down in its travel which is not a good idea. A Watt's link by comparison only allows the rear axle to move in a virtually perfectly VERTICAL line which is what the leaf springs naturally want to do so they will have no additonal spring rate added and the rear axle will operate much smoother than with a Panhard bar setup.
The only other thing to do at the rear axle is to install control arms. I prefer the later under spring type control arms but you have to keep in mind that you need to allow for pinion angle changes with these control arms and be certain to set your rear ride height with the under spring control arms level with the ground or you will get roll induced oversteer that can be quite surprising.
Add adjustable anti-roll bars to balance front/rear handling once you have your basic spring rates and have selected wheels and tires. On these early cars body roll is less of an issue as far as handling and geometry goes but of course flatter is going to be prefered by most drivers. But when picking anti-roll bars for the car you need to keep in mind that your front roll stiffness will be noticably higher if you relocated your upper front control arms.
I mention them last but the most important suspension parts are your dampers. Bilsteins valved for a range of springs rates are available as are the correct Koni dampers. Koni's are adjustable but are still pretty stiff for a street driven car.
HTH!
66 fastback suspension setup for HPDE 
