I got a 4x4 1986 k5 chevy blazer and im getting 12 inch lift with 40i

I got a 1986 k5 chevy blazer and im getting a 12 inch lift with 40inch si tires, before I do that I would like to know what do I have to get so my truck won't break down. I've heard I might have to upgrade the rear end but im not sure how long it will last with a stock rear end.

Thank you for your help.

my email is gusflores22@gmail.com and any info would help. thanks  

If you're putting 40's on it you would for sure want to swap the axle out to 1ton gear, Dana 60/14 bolt. You're stock axle will laugh at you.

What engine do you have?

You'll also want to make sure that you are geared accordingly. 5.13's would probably work well for you.

Do that and you should be good to go.  
-------------------------------------------------------------
Long Travel 4WD - The best of Both Worlds

Questions? Comments? Concerns? PM Me!

I have a v8 350 engine. thanks on your info. so if i were to just get the lift i wouldn't need anything. only need upgrades for the tires?  

You will need new driveshafts and your driveline angles are probably going to be quite severe. You will also need to correct your steering angles if the kit doesnt already have the parts to do so. A drop pitman arm and/or high steer knuckles would work. You are going to need to extend your brake lines as well..  

superlift makes a really good kit for your truck. it comes with every thing your gonna need except for drive shafts. i would wait to do your drive shafts until you put a set of one ton axles in it.