[1969k10stepside]

You could use a 14 bolt which are practically a dime a dozen rear or stick with a Eaton axle,which some swear are stronger than the 14 bolt.The eaton axles..found in the rear of 3/4 and 1 ton 67-72s and the 14 bolt was used in the 3/4 and one ton trucks from 73-??.The dana 60 front will be found in K30s or V30s.Keep in mind,if you find a one ton 4wd (K30 & V30) and use the 60 front from it,the rear axle (14 bolt) will go into the blazer without having to move spring perches,like you would on a 3/4 ton axle.You would just have to relocate shock mounts.
Dana 60 fronts can be found cheap if you look long enough,but if not be prepared to spend around $1000 for one.There is the DRW style,and the SRW style.The difference is in the hubs.You can use the dually style on yours if you have the right rims,but if not you will need to convert to SRW hubs,or just buy a SRW dana 60.The SRW style are usually more expensive,as are hubs if that is what you need to convert a DRW to SRW