I looked in the 68 service manual.For alternator specfications and found no number.I have the equiv to what the dealers had back in the day in the binders on a CD .It didnt say 426.But showed for all small block big block & AC .These were the numbers I seen 2098 850 3000 010

1969 Daytona 440 L9B410772 1970 Coronet 500 383 Presently owned 1970 Superbird 440 U 166242 1970 Superbird 440 U 174597 1970 Superbird 440-6 V 179697 1970 Coronet RT 440 U 224126 1968 Road Runner 426 J 134509 1970 Daytona Replica 318 G 178701