I am putting a 3.4 in a 84 4runner with a bellhousing from a 3.0 and a r151 from a turbo truck. The question i have is after all is said and done if the transfercase will be in the same location as the stock one,will drive shaft lengths remain the same length or will everything need relocated and lengths changed. Am planning on only putting 4.7 gears in the transfercase and hopfully using stock length drive shafts. If the shafts need changing and a new crossmember will be needed,then i might as well put a doubler in it as well. Thanks

 

Its not so much the transfercase as it is the location of the companion flanges that matters. If they are in the same spot as the original flanges then you don't need any driveline mods.

I didn't need to modify the rear driveshaft but did need to have the front driveshaft lengthened almost 2".