NOTHING! Heads are the same I believe 4.8 has 862 and 5.3 has 706 or something like that....you current oil pan will transfer over...It will be a very easy swap..You dont need any accesories......You can use you current PCM and harness...just might wanted to get it tuned for a 5.3 before it goes in or somethin..or get the 01 PCM from the guy and get someone to tune it then put it in in the swap

If interested let me know and I will get them to hold it for you!

you can sell everything you currently have for the same price easily ...so basically you would get it for free in the long run lol