What is the difference between a eddy 1405 and a 1406

CFM same, Main jet primary 1405 = .100"- 1406 =.098 , main jet sec. same , metering rod Pri. same , step up springs 1405 = org. - 1406 = yellow , pump drive location 1405 = middle hole -1406 top hole , accelerator pump nozzle Dia. 1405 = .028" - 1406 .031" and the choke , but everything else is the same .