Presumably the 4AC had essentially the same specs as the 4AD with the following differences:

• Cylinders - 65 mm. by 90 mm. = 1,195 c.c. and some 65 mm. by 89.4 mm. = 1,188 c.c.
• Back axle ratio 5.143:1 (Moss)
• Carburator - choke 24; main jet 125; correction 230