I agree with you on the 350. It earns the right to be called "legacy." But the LS1 was rolled out the last year Acura made the NSX. Variable valve timing had been on production vehicles for seven years. The DOHC ZR1 V8 was a six-year-old design, out of production for two years. CARB standards were going up, not down, and efficiency suddenly fucking mattered. And the parts availability should be an order of magnitude more than it is: LS1 parts should fit on 350s and 350 parts should fit on an LS1. But they're mutually exclusive. It takes a company like GM to keep all the dimensions (bore, stroke, piston center, crank center, cam center, rocker length) yet ensure that the old parts don't fit on the new and the new parts don't fit on the old. Because you're right - a new engine is a risk. But Chevy rolled out a new engine that has all of those drawbacks and none of the benefits from, you know, designing something actually new.