Changing rack shafts?????

[Hoosier78]

Has anyone tried to change a rack shaft in a Sweet Mfg. rack and pinion. We have a spare 18 1/4 rack for a blue front rocket, but need to convert it to a 19 3/4 for our black front. We have all the pieces, just want to know if it is doable so we do not have to send it into Sweet. \


Thanks