The Tahoe I priced out had the 6.2 liter version of the same engine. The GM 5.3/6.2 has little commonality with a 1960s 327. The 5.3/6.2 is architecturally based off the 1997 Corvette C5 LS1, which was so different from a 327 that the only similarity I can see is a 90 degree V8 architecture and a single cam-in-block / OHV strategy. Even the LS1 block architecture is different, as the cam is higher up in the block than the old design, because they wanted shorter pushrods. The 5.3/6.2 includes continuously variable valve timing and cylinder deactivation under light loads, direct fuel injection, and completely different intake, exhaust, and ignition systems. This is essentially all new technology with dramatically increased complexity, and any reliability advantage from being an architectural derivation from a 1960s engine is, IMO, non-existent. I'm not a truck guy at all, but catching automotive news clips now and then shows that these engines are not especially trouble-free either, but GM seems determined to stick with large displacement naturally aspirated V8s while trying to maintain competitive fuel economy. Not that I'm picking on GM, Ford and Ram seem to have similar strategies for their heavy duty models. The few people I know who are serious about towing get the diesel versions with all three brands.
The GM 10-speed transmission, which was created in a joint development with Ford, has no lineage to a Turbo 350.
A body on frame design is superior for towing, but you can get that from GM, Ford, Ram, and Toyota. I am grateful trucks have never fascinated me. I have enough expensive preferences as it is.
