There's a lot other items to consider.
Did a lot of considering, number crunching and agree. I don't really "need" the 383, just want it. But the 350 has been great to me; I plan on putting it in the old truck because it should last another 50K before needing a rebuild (first one for me). After crunching the numbers, I'll be swapping for a crate 350 with new accessories, etc. I'll be putting the old L31, minus fuel injection (unless I can find the parts for it at the junk yard) into the pickup.
I've never done any mods to the Yukon, yet, and one of the first things I'm looking at is the exhaust. Is there actual real duel exhuast? The only place the pipes come together is at the muffler on my Yukon. So I'm looking at long headers and then new muffler and pipes (cats have 60K on them). I can do mods and add some HP as time goes on. I don't have the skill sets to replace a cam so bolt ons are about the most I can do. I'll do some more searching