I am putting a 6in. rough country lift on an 87 chevy 3/4 ton and need to know if i am going to have to lengthin the driveshafts, i am really hopeing not. the one guy i talked to thought i would beable to get by with it. Let me no what you think. thanks  

You need to lengthen it. Simple geometry here. If you use stock shaft if is going to reduce the contact are for splines in slip joint a good bit. Any good drive shaft shop can lengthen it easily. I would also have then install CV's in front drive shaft to prevent vibration for drive line angle on shorter drive shaft (BTW, it should be lengthened too) BTW, make sure you extend to bump stops that limit compression of suspension with new lift because when you lengthen drive shafts for lift and then bottom it out to old stops, you run a risk of damaging tcase outputs when drive shaft bottoms out in length and applies force to tcase.  

i agree w/sno whenever you go over 4" you need to lengthen shaft,no ifs ands or butts about it,if your spebding the money to lift you need to spend the money to get the power safley to the tires...just like sno says too long will damage tcase...and not legthened will put strees on the out shaft splines.  

how much will it cost to get them lengthend and balanced do you think? im kinda on a limited budget but but i gus if i dont do it right the first time i will pay more in the long run. thanks for the help.  

o and one more thing im still 15 so the only time i drive the truck is messin around on the farm so will it be ok to drive it a little bit until i turn 16 and get some money to lengthin them, tires, wheels and lift have got me kinda broke.  

You strip out splines or throw drive shaft it is going to cost you a lot more to fix.  Fix it now or park it.  

ok thanks what do you think it will cost me to get them lengthend and balanced?  

I cannot say what prices are there but here is would be below 100 bucks. A nice drive shaft shop has machines that make short work of it (even the cutting and welding)  

if i remember right i had my shaft legnthened w/new joints and slip yoke, balanced and a new paint job for $225 but seein how todays money is, its probably gonna be higher....  

keithpapa:
if i remember right i had my shaft legnthened w/new joints and slip yoke, balanced and a new paint job for $225 but seein how todays money is, its probably gonna be higher....

Yes but you did not have a simple cut/lengthen and balance. I had a bush hog drive shaft repaired a few years about and they put a new end/yoke on it and all new joints and it was under 100 bucks. (and let me tell you, that drive shaft was HEAVY too)