Something tells me Bent knows how to build a stout small block. As big of a fan as I am of the LS swap, I know the expense from the fact of doing it. And mine was done with a freebie engine (yes high mileage), but it's all the ancillary parts and pieces that add up quick. If my 91 came to me with a TBI 350 like it was built with, I'd probably still have it in there and still be in savings mode for the LS swap. I just had to bite the bullet since mine had no engine. So MAW swap in the 5.3 right?
I'm probably going to still going to switch from running a MEFI4 controller back to a GM 0411 PCM due to lack of tuning support for the MEFI4 platform. Which will dictate a complete engine harness change. But at least by running the GM PCM I can use a standard Tech2 scan tool or any aftermarket OBD2 adapter and an app on my phone or Ipad. Bottom line is more $$$$.
LS is a steep learning curve for sure. If you are more comfortable running the OG SBC then run it. Money saved on adapter brackets, LS specific accessories, harness, Controller and refreshing a LS, you can buy some killer heads and run a better aftermarket self learning TBI system for a great torquey stump pulling SBC.