the space on the axles should be a bit more then the cross pin I.D or clutch spring block what ever hits first . the posi side of the clutch drive hub is first and side gear set last on this side so around 1. inch air gap or a abit more but 1 7/8 may be a bit big of a air gap . that why i always mark axles spines. then i could check engagement measurement of the spine pull them out a 1/8 or so they did not bottom out on cross pin when wheel bearing was seated. Mosser did most all the re spine or new axels for me so they knew what the air gap needed to be. but on used stuff like axles with out housing you have to work all this out alot of measuring i have not played with one in sometime ....old timmers