changing rear gears need a little help

[Scottcoda]

I am trying to put in a 3.54 gear set into my 68 gmc 3/4 dana 60 that was orignally 4.11 (4.10) but it seems the 3.54 gear is too big for the carrier, even if I remove every shim the gear seems as though it will not fit.. is it possible that the gear set I bought is for a different type of dana 60, age, type etc etc.. there is a link to the gear i bought.. thanks for any help..

http://m.ebay.com/itm?itemId=371029672055