I have a 1970 Chevy 1/2 ton i am wanting to switch my axels to either 3/4 or 1 ton. I was also going to put a 6inch suspension lift on it and three inch blocks.  I would like to know what year of truck will interchange with mine. If anyone knows any information on this please let me know.  

i did a swap like what your talking about on my 1/2 ton blazer, what you need to find a 73-87 3/4 ton or 1 ton truck,and get those axles, the axles should be 8 lug dana 44 in front for a 3/4 ton or a Dana 60 front for a 1 ton, the rear axle can either be a semifloting 14 bolt 9.5 inc ring gear or the big dog 14 bolt full floater 10.5 inc ring gear(i used this one)  Your going to need a combonation u joint for the rear axle to allow you to run 1/2 ton driveshaft with 1 ton axle or get a custom driveshaft so you can use regular off the shelf u joints which are cheaper and easier to find  

i did a swap on my k10 for 3/4 ton axles and used the same driveshafts without changing u joints.  the rear was your standard 14 bolt and the front was the 44.  both driveshafts worked fine. is this a problem? or are they different driveshafts, because i have an NP205 trans case on the truck as well.