IMO, the LS craze will fade eventually with the introduction of the next generation of GM engines.
With that said, I did purchase a LQ9 for my 67 build. My main reason was I'm familiar with the engine and feel comfortable working on it. Also, it was easy on the budget.
If I were shooting for a value add motor and had the cash, I'd have to go 572 BB with a carb. I personally think that will always be cool.
