Early 1968 GTS Fender Tag question...

No but they do not stop just fine from 130 mph they fade badly after one hi speed engagement they become unsafe to continue until they cool
normal driving they work ok
ma mopar dropped the ball there imo
all 340 383 440 cars should have had the kh/disk std equipment or all v8 cars imo

Most all performance musclecars from 64-69 came standard with drums. Discs were optional on most all too at an extra cost. Drums kept the standard price down.

Mopar did make discs standard on 70 Duster 340.