That swap was not a lot of fun, I won't lie. There are easier ways of doing that swap now. As for the motor mounts and what not, they are all the same, everything will convert over, your serp system might give you a little trouble depending on the waterpump and drive system you use. Truck or Vette. There is a new harness you can buy now that converts the gen III 24 tooth setup to the gen IV 58 tooth setup. Might wanna look into that for your swap. Hope this helps a bit.

maybe you can help me out, i have a 01 gmc sierra ext cab z71 and was considering the same exact ls3 swap you used. i have the 5.3 now and wondered if all the engine mounts are the same and if a set of headers for the 5.3 will work on the ls3 also what else i may need to make it come to life other than getting my pcm redone? any input would be greatly apperciated. thanks