+1 for the Porterfield R4-S Shoes.
Before the power disc brake swap I had them one mine, too. The stopping power was way better in comparison with the stock ones. And the fading when the shoes getting hot almost disappeared.
When you buy them just make sure that you selected the R4-S ones. There is also a R4 version available but these are for track use only.
'68 Mustang Coupe
289cui V8, C4 Trans, Hughes 2200Stall TC, Speed Pro Forged Piston 4.030", AFR 165 #1399 heads, Ford Racing E303 Cam, Lunati Link-Bar Lifters, Edelbrock Performer RPM Intake, Edelbrock 500cfm carb, Pertronix II billet distributor, Hooker Competition Long Tube Ceramic Coated Headers, 2,5" Flowmaster American Thunder SS exhaust with Dynomax Ultra Flow SS mufflers, 8" rear /w 3.25:1 and trac lock posi, 15x7 TTD 215/65R15, Borgeson Steering, CSRP 4-piston power disc brakes