Something just went wrong with my 99 Yukon 4x4 with 5.7 v8... runs, but oil pressure dropped and metal shavings in oil. Too much invested to scrap and no trade-in value as is, so going to put in a new engine. My question is... with the newer 6.0 work with my 5.7 heads and injection? Would like to get more torque for towing. Has anybody done this swap?  

350 parts will not bolt on a 6.0. Different block/motor. Also 6.0 has a different bellhousing bolt pattern. 350 Vortec is a competent engine and if you fell it is lacking in towing power you need to be looking at your axle ratio not a slightly bigger engine. Also ECM and wiring harness is different too. Sure it can be done but it is not the answer to you orignal problem.  

Hmmm... will the factory computer and injection system handle a 383 stroker? Gonna' have to look for other gearsets too, got 3.42 and want to get 4.11's.  

no factory stuff will not keep up with a 383. gonna need bigger injectors and reprogramed pcm