Gasoline engines with eight cylinders are becoming increasingly rare except in luxury vehicles or heavy-duty pickup trucks. Or, in this case, luxury heavy-duty pickup trucks. On premium gas, the sonorous 6.2-liter Ecotec3 V-8 under this hood is rated for 420 horsepower and 460 pound-feet of torque. With the 10-speed automatic transmission and the trailering package, this gives us a tow rating of 13,300 pounds, enough for a top-of-the-line Airstream, the 33-foot Classic.

The Denali Premium Suspension with magnetic ride-control dampers adapts well to ordinary, non-trailer driving too, at least for a pickup with a Gross Vehicle Weight Rating of 7,100 pounds. A knob on the dashboard lets the driver select Normal, Sport or Off Road driving modes; I’ve been tooling around in Sport mode because that seems to erase about one-third of the GVWR all by itself.

GMC, General Motors Corporation, reserves the Denali moniker for its poshest trim level; maybe we should say its highest trim level, as Denali (ex-Mt. McKinley), the mountain in Alaska, is the highest point in North America. “Denali” trim is available on a number of GMCs, including the Yukon and Acadia SUVs, the Canyon midsize pickup and its lookalike big brother, this full-size Sierra. They wear it well—the Sierra Denali Ultimate cabin is a pleasing blend of utility and full-grain-leather luxury without the Las Vegas glitter of some fancy pickups.

Leaving aside cabin air fragrance spritzers, mood lighting and a wine cooler, when it comes to accessories and features, this costly truck stands shoulder-to-shoulder with many deluxe sedans. The window sticker spans two windows and details a long list of performance, mechanical, tech and safety features.

The safety systems begin with automatic high beams, cover the latest generation of collision alerts and braking assistance, and extend to front and rear parking assistance and a crisp two-view backup camera. Happily, there’s no annoying tugging on the steering wheel when the vehicle gets close to a lane divider—except under cruise control; more on that later.

The highly adjustable front seats are heated and ventilated and offer (GMC says) 16 combinations of power massage; the commodious rear bench seat splits 60/40, with a storage bin beneath and a fold-down center armrest with cupholders, and each side is individually heated. Open a door and running boards power out from beneath the body to let us step up and in with some dignity.

There’s a power sunroof too, as well as a 12-speaker Bose stereo and a large touchscreen loaded with apps for trailering, navigation and communication. In a final nod to truck-ness, there are tow hooks (chrome-plated) in the front bumper and, at the wayback, GMC’s Multipro tailgate.

The sticker price on this deluxe truck is $87,190. This includes $495 for metallic paint, a $1,995 destination charge and $2,200 (plus, after three years, a subscription fee) for Super Cruise. This is GM’s hands-free driving system; on the right roads and with decent weather, it is brilliant. Especially in stop-and-go traffic and on long trips, it can be a competent co-pilot that never gets tired.

Super Cruise uses map data and GPS (constantly updated), OnStar Emergency Services, a lane-tracking camera and other safety sensors to monitor and manage the vehicle’s position, heading, speed and proximity to obstacles and other traffic in real time. It functions very well—on compatible roads, which I take to mean roads of sufficient width with clear lane markings.

GM claims there are 400,000 miles of such roads across the US, and even provides an interactive map. However, plugging my ZIP Code into the search box shows just one Super Cruise-compatible road near me: Us Rte. 1. And I would bet that snow, sleet and possibly heavy rain—anything that obscures lane markings—will defeat Super Cruise on Rte. 1 or any other highway. But that wouldn’t stop me from adding it to any GM vehicle.

Next week: Acura MDX Type S