Sorry for getting back late. No, the bracket is very thick at least a 1/2 inch. The reason is because it needed to be the correct thickness for the caliper to be in the correct place on the rotor. Nice piece....really...
So on the GM calipers a splitter valve is used. What is the purpose GM uses it? I will attach a copy of the instructions for ya all too read.
1962-72 Mopar Front Disc conversion instructions
1. Crack front wheel nuts loose, chock up rear wheels.
2. Jack up front end of car, support outer ends of lower control arms with jackstands.
3. Remove front wheels, drum/hub assembly.
4. Take drum/hub assembly and cut swedge on studs, then remove drum by press or with mallet. This may destroy studs, if so, replace with ¼” or more longer studs. Check to see if drum hub fits inside rotor. If not (unlikely), take hubs and rotor down to machinist and have him trim the outer flange to fit inside the rotor hat.
5. Disconnect brake flexible line. Undo lower drum backing plate nuts and remove upper drum backing plate nuts and bolts. Carefully remove drum backing plate, it may be under some tension. Clean off spindle assembly.
6. Place adapter plate over bolts, insert remaining top bolts, torque all nuts to spec, should look like this:
7. Note how welds on caliper pin nuts face inboard…
8. Check lug nut engagement depth. Do this by setting loose wheel face down on sawhorses. Lay rotor inside in assembled position, then place wheel hub inside rotor. Look up at face of wheel, thread a pair of open lug nuts onto studs; studs should protrude slightly thru lugnuts for safety.
9. Clean and repack wheel bearings. Replace seal. Assemble hub onto spindle, tighten outer nut to spec, then secure with keeper, pin and dustcap.
10. Place rotor onto hub, and run two or three lugnuts down finger tight ot retain rotor. Wipe down rotor with alcohol, lacquer thinner or other cleaner to remove grease and oils. Wash hands.
Assemble pads into caliper, and slide assembly into caliper bracket, lube with silicone grease then screw in new slide pins, tighten to 35 foot-pounds. Check fitment and rotate rotor to check clearance.
11. I used 1977-78 Chevrolet Caprice front hydraulic hoses; these may be too short (12”) for you application. 1976 Chevrolet Chevette hoses have the same ends, but are 15” long, and need some file work at the banjo end. Another hose that may work better is the 67-70 Caprice unit. This hose screws directly into the side of the caliper. Use a piece of rope to find the optimal length for your application. Install hose with new copper crush washers.
12. Master cylinder and proportioning valve specs are quite varied. I would recommend 1971-72 Dodge Charger disc master cylinder for best performance match available in both power and manual flavors. Prop valves are of the same vintage. Some have run with the drum dual master distribution block, not optimal, but works fine, and can be optimised if run with a adjustable prop valve.
13. Bench bleed disc master cylinder, mount on car, then bleed entire system and test.
Part Application NAPA Wagner Raybestos
Rotor (2) 1998 300M front (perf.pkg) 86777 BD125638 76777
Caliper, LH 1969-72 GTO front 242-2016 CR76062 RWC5052
Caliper, RH 1969-72 GTO front 242-2017 CR76063 RWC5051
Hoses (2)* 1977 Caprice front (12”) 36797 F97664 BH36797
Hoses (2)* 1976 Chevette front (15”) 36832 F86572 BH36832
Brake pads 1969-72 GTO front AE728A ZD52 RRD52
Caliper bolt (4) 1969-72 GTO front 82205 F76075 H5002
*verify fit and length before buying
Scarebird Mechanical 1 January 2005