One problem your not thinking of is the t case,The newer trucks like the 4l80e is in uses the wrong side drop t case.I believe you can use a np241 from a 88-91 k5/suburban or use a adapter kit and run a np205.And again using the nv4500 you will probably be stuck doing the same thing use a np241 or a adapter kit.As far as swap parts
http://pacificfabrication.com/63-72-...ssmembers.html and
http://dirtydingo.com/store/product_...oducts_id=1408 both are a engine crossmember.The trans/tcase mount your kinda on your own to rig up,Most take a stock one and move/ cut and mod it to fit.