SD-49 is the listed developer:

Kodak SD-49
Color negative motion picture film developer for Process ECN-2

Water (21 – 38C) 850 ml
Kodak Anti-Calcium No. 4 2 ml
Sodium sulfite (anh) 2 g
Sodium bromide (anh) 1.2 g
Sodium carbonate (anh) 25.6 g
Sodium bicarbonate 2.7 g
CD-3 4 g
Kodak Antifoggant AF-2000 5 ml
Water to make 1 l

pH at 25C = 10.25; density = 1.029

Develop 3 minutes at 41.1C (106F)

PE's comments about contrast and stability should be taken seriously. If you are going to scan the negatives, motion picture film negative will probably work.