Ok, I am getting ready to swap in a 5.3 in my 2000 4d 4wd, and I can't find a difinative answer on the torque converter issue. Heres my idea, the trans in it now is from a late 90's full sized gm with a 350 vortec, I have a 4l65 from a 03 Tahoe, and I am wondering if I can just switch the torque converter from the old style small block one, to the new ls one, and make up for the offset of the crank shaft. Any ideas would be appreciated, and the reason I'm not putting the 65 in with the V8 is becyi don't have the money to build it up to the trans. Thank you for looking at my three..

 

Does the vortec trans have a removable bell housing?
Im willing to bet that the Vortec 4L60E converter will not be compatible with the newer 4L65E trans due to the trans input shaft. you will have to see once the trans is out what input shaft both transmissions have.
This may help some to show the differences.
https://ls1tech.com/forums/automatic...s1-4l60-e.html

 

Thank you for your imout, it would appear that, it is different, and for my sake of having less headaches, I will just wait and rebuild the 65 and out in a brand new drivline instead of taking the risk.