Brakes/Suspension
a big project
The car was originally an inline 6 model, complete with four-wheel drum brakes, four-lug wheels, and a rear axle not rated for the V8's power.
We upgraded to a Ford 9 inch rear end with 3.25 gears (70mph at 3000rpm with the current tires), 31 spline axles, 11 inch rotors, and 1985 Cadillac Seville calipers. In the front we went with CSRP SWAP.2 Grenada-style spindles, which I believe are modified slightly to correct any bumpsteer issues. The spindles are coupled with Grenada rotors and calipers, all part of the CSRP kit.
The Cadillac brakes proved to be a nightmare to get right. These calipers are old, from the early to mid 1980s, and the refurbished units on the market seem to be very questionable. We had to order many sets to find ones that wouldn't leak, ultimately finding luck with a company called A1 Cardone who put "pressure tested" in their product descriptions. Once we had working calipers the trick to bleeding them seemed to be to detach them from their brackets so that the bleed screws were perfectly horizontal, placing the internal bleed hole at the very top of the cylinder. Because these particular brakes behave more like drum brakes than disc brakes we also added a 10lb residual pressure valve to the rear lines.
Going to four-wheel discs also necessitated power brakes and we then found ourselves with too little pedal feel. Here we needed to play around with different master cylinder bore sizes, eventually settling on a 1 1/8 inch unit from a late sixties Corvette. The brake pedal in the car was designed with a 6 to 1 mechanical advantage, so we altered it by moving the pushrod pin down by one inch, resulting in a 4 to 1 advantage (the pedal is 12 inches long, the pin was originally two inches from the pivot point and we moved it three inches from the pivot point). New pins can be bought from www.MustangSteve.com. If you decide to go with a custom brake setup, know what you are getting into!
In terms of ride height, the front sits on 205/55R15 tires, uses the CSRP Grenada spindles mentioned, 1" lowering springs, and we lowered the upper control arm mounting point using a 1" "Shelby drop" template from DazeCars.com. The steel where the A arms attach seems extra hard, so we ended up drilling the mounting holes using drill bits that increased in size 1/64th at a time.
The rear tires are 235/60R15s, the axle tubes are 3" in diameter, the springs are standard V8, and there are pinion angle shims between the axle and springs that lower the back by another 1/4"-1/2" or so. Beneath the springs are Lakewood traction bars, and they are angled slightly upwards by additional shims.
Either the frame is bent, or the springs have slightly different arcs (more likely), because the driver's side rear sits at a slightly lower height than the passenger's side. I like the look of the driver's side better, and would even go a little lower, but between the 3" axle tubes and the fat tailpipes there is no more room under the car.