Meh, I vote TBI but, that's just me
With apologies to the Mopar 318, but none to the LS motors, the TBI motors may be the longest lived cast iron V8's ever devised by humankind......
Donning my flameproof suit........
It's simple, the TBI's operate at lower RPM's. Less RPMs for every mile driven translates into less wear. LS motors have higher HP potential, lower emissions potential, all in a slightly smaller package, albeit at higher RPM's than the TBI or 1st Gen Vortec.
The Vortec V-8's fall somewhere in-between.
The SBC have 45 years of R&D, and the Vortecs are the culmination of that. Particularly reliability. I"m old enough to remember when any engine was "wore out" when it crossed over 100k.
I know I'll catch flak, but.....all things being equal, the Gen 3 LS motors do NOT last longer than the TBI's or the Vortecs--notably dependent on level of maintenance and how it's driven.
I've owned all three of these engines, and I've owned 2 of them when relatively new and I know the provenence of ALL four of my pickups noted in my sig and am/was the second owner of all four. They all were fairly well maintained and driven fairly sane. Importantly "well maintained" also means keeping the truck relatively clean beyond the interior and the shiny side. It also means keeping the chassis and engine bay clean. I see photos on here all the time of filthy engine bays and rusty trucks. Plastic and rubber doesn't like to be covered in grease and road grime. Road salt and mag chloride love to rust metal.
My 96 and 97 ECSB's have no rust in the corners of the x-cab. Why? Because I and the previous owners washed the underside of the truck often. Even though I own pressure washers I still hit the carwash (especially during the winter) often. I almost always spend more time (and money) washing underneath and the engine bay than I do the paint.