Not wanting to argue with the LS crowd. It's a great motor for sure, I'm just saying that calling the 350 "undesirable" sounds crazy to me. You can't swing a dead cat without hitting a vintage vehicle that someone has put a 350 into and loves it. 350's are abundant, parts are cheap, and they are easy to work on. Is the LS better? Sure, but I'm happy with the 350 that I put into my c10. It can smoke the tires effortlessly, is reliable, and looks great.
The other day, I swapped my carb. In and out in 45 minutes. Same thing for the waterpump when it went. LS's are too complicated to work on for a guy like me.
In the end, it's up to what you want. Both options can be winners!
Here is a pic of my 350 craiglist motor ($800.00) that I put in myself, wired myself, and keep running myself (no white lab coat necessary).