We’ve already observed how GM was unique among the Big 3 US automakers in having bespoke V8 engines for each of its five automobile divisions. Contrast this with Ford Motor Company and Chrysler Corporation, both of which were sharing V8 engine architectures among their various brands since the 1950s.
Today, division-specific powertrains at GM are a distant memory, and all engines are now simply “GM” engines. So when (and how) exactly did this transformation take place? Note that I’ll be limiting my discussion to V8 engines in this post: Six and four-cylinder engines (which were shared much more freely at GM) will be the topic of a future post.
Even for a company as big as GM, it is expensive to have distinct small- and big-block V8 engine families for each division. It didn’t take the bean counters at GM long to realize that this was not a sustainable situation, especially once GM’s market share began its long slide from its peak of 50% in 1962. Cracks appeared in the facade starting in the 1960s as GM divisions began to swap V8 engines, with the practice entering public consciousness in 1977 with the breaking of the Oldsmobile-Chevrolet engine scandal.
GM learned their lesson after the 1977 scandal, and the lesson was the correct one: The issue wasn’t so much that engine swapping was bad (after all, Ford and Chrysler were already doing it). Rather, the problem was the failure to properly disclose the engine sharing and, and more broadly, the continued use of divisional specific engines and divisional engine branding. After 1977, GM engine swapping rapidly picked up speed, so it wouldn’t be long before some divisions stopped making their own V8 engines altogether and made the switch over to “corporate” powertrains.
When I first hatched the idea for this article, I was surprised to find that I couldn’t answer the question posed by the title, and I’m guessing that many of our readers can’t either. But perhaps I shouldn’t have been so surprised: GM didn’t make a lot of noise at the time about the “last Buick engine” or “last Pontiac engine,” and for a good reason: Aside from the 1977 scandal (which was largely manufactured by lawyers and amplified by the media), buyers typically didn’t care. As a result, all of GM’s division-specific V8 engines snuck out in the middle of the night with a nary whimper.
Buick was actually the first GM division to share its V8 engines with other brands, going all the way back to their all-aluminum 215 cu. in. V8, which first appeared in the 1961 Buick Special (a full 16 years before the 1977 engine scandal). This engine would be used in the 1961-62 Pontiac Tempest and in the 1961-63 Oldsmobile F-85 (the latter application employing a modified head and angled valve covers to make it look more like other Oldsmobile engines). The Oldsmobile version of this engine would also gain a turbocharger in 1962. This initial experiment in V8 engine sharing would be short-lived, however. By 1964, each division was using their own V8 engines in their senior compacts. Almost a decade would pass before any GM division would share a V8 engine again.
Buick first started using V8 engines from other divisions with the 1975 Skylark, which used the Oldsmobile 260 V8 for its smallest V8 engine option. The 305 Chevrolet small-block V8 was also available in the Skylark starting that same year.
By 1977, the engine sharing floodgates were wide open at GM, and the Oldsmobile 403 V8 began to show up in the Buick LeSabre, Electra, Riviera, and Estate Wagon. The Chevrolet 305 would show up in the Regal in the following year.
While Buick may have been a judicious engine borrower, they were a stingy lender: Their V8 engines rarely appeared in non-Buick branded cars. Because of this limited reusability, Buick, the first division to share its V8 engine, would become the first GM brand to stop making its own V8 engines in 1980. The last Buicks powered by Buick V8 engines were the 1980 LeSabre, Electra, and Estate Wagon. After that, all V8 engines sold by Buick were sourced from other divisions.
As an interesting footnote, GM sold the tooling and design of the aluminum 215 V8 to Rover in 1967. Variations of this engine would remain in production (as a Rover V8) until 2003, outliving its successor Buick V8 engines by several decades.
Pontiac was not as promiscuous with their engines as some of the other GM divisions, with most of their V8 engines being used in their own cars, which put them in a similar position to Buick by the late 1970s.
That said, Pontiac holds the second-earliest example of V8 engine sharing at GM that I could find (after the 1961 Buick 215 V8): Specifically, Pontiac was using a Chevrolet 307 V8 as the optional V8 engine in the 1971 Ventura. Indeed, at varying times over the course of its six-year run, the Ventura would be sold with V8 engines made by Chevrolet, Oldsmobile, Buick, and Pontiac, making the Ventura one of GM’s biggest ever engine transplant recipients.
The new for 1977 Pontiac 301 cu. in. V8 was used in various Buicks from 1977 until 1981. The peculiar Pontiac 4.3 liter 265 V8, a de-bored version of the 301, appeared for only two model years, 1980 and 1981. In addition to Pontiac vehicles, this engine was available in the Buick Regal, Buick Century, and Oldsmobile 88.
One year after Buick ceased making their V8 engines, Pontiac would be the next GM division to completely stop making its own V8 engines. The last Pontiac V8 engines were built in the 1981 model year – thereafter, Pontiac used GM V8 engines sourced from other divisions in their cars.
As I mentioned at the beginning of this article, Oldsmobile famously started using Chevrolet 350 V8 engines in the Delta 88 in 1977. Still, Oldsmobile on the whole was more of an engine donor than a borrower, with their 350 and 403 V8 engines picking up the slack over at Buick and Pontiac after those divisions stopped making their own V8 engines in 1980 and 1981, respectively.
Oldsmobile was also the sole maker of passenger diesel engines for all of GM in the 1970s and 1980s, which were used by all five automotive divisions. Actually, GMC used the Oldsmobile 350 diesel V8 in the Caballero from 1980 to 1984, possibly making this (along with the SBC) the only engine to ever be used across all six traditional GM divisions.
Oldsmobile would stop making the 403 in 1979, and the gas-powered version of the 350 V8 in 1981, although the diesel would stay in production until 1985. A smaller 307 cu. in. V8 would stay in production until 1990, and would eventually be used by every GM car division (excluding Saturn). 1990 would mark the end of Oldsmobile produced V8 engines at GM.
The Aurora would debut in 1995 with a DOHC V8 engine, but this was a derivative of the Cadillac Northstar engine and not an Oldsmobile design.
Cadillac was the only GM division to never share its OHV V8 engines with any other division (although the modern DOHC 32-valve Northstar engine would eventually be shared with Oldsmobile, Buick, and even Pontiac).
Cadillac began borrowing V8 engines from other GM divisions in 1976 when the Seville launched with an Oldsmobile 350 V8 as its sole engine. Granted, the 350 in the Seville was fuel-injected, while all other applications of the Olds 350 that year were still carbureted.
Starting in 1986, Cadillac began using a variety of Oldsmobile and Chevrolet V8 engines in their cars to supplement the trouble-prone Cadillac-exclusive HT-4100 V8 engine. Variations of the Cadillac High Technology (HT) engine would continue to be used in Cadillacs up until 1995, as the Northstar V8 gradually started replacing it beginning in 1991.
As previously, mentioned, the Northstar V8 would be the first Cadillac engine to be shared with other GM divisions. It would go out of production in 2011. You might think this would be the end of the line for Cadillac-branded V8 engines, but there was one more.
Cadillac’s last exclusive engine was the 4.2 liter Twin-Turbo “Blackwing” engine, used for only one model year in the 2019 CT6-V. With an estimated unit cost of $20,000, this is easily one of GM’s most expensive (and short-lived) engine flops. Note that newer (post-2020) Cadillac Blackwing engines have no relationship to this engine: The CT-5 Blackwing uses a supercharged 6.2L GM V8, while the CT-4 Blackwing uses a twin-turbo V6.
So Cadillac earns the honor of being the last GM division to produce its own V8 engines, and quite recently too.
Chevrolet is the Type O-Negative (universal donor) of GM, its V8 engines having been used by every car and truck division. Detailing all the Chevrolet engine sharing would take more space than I have here, so I’ll just cover the highlights here.
As previously mentioned, the 1971 Pontiac Ventura was the first non-Chevrolet car to receive a Chevy engine. By the mid 70’s Chevrolet V8 engines were regularly appearing in Pontiacs, Oldsmobiles, and Buicks, and could even be found under the hoods of Cadillac cars and trucks starting in 1990.
While Chevrolet may have been a prodigious donor, other divisions’ V8 engines almost never appeared in Chevrolet-branded cars, with the Oldsmobile diesel being the only exception I could find.
The Chevrolet small-block V8 would go through several iterations of refinement over the decades, gradually losing its Chevrolet branding to become a GM V8 engine (ultimately in Generation I and Generation II guise). The automobile-only Gen II would last appear in the 1997 Camaro and Firebird, while the predecessor Gen I would continue to be used in various truck applications until 2005. The successor GM LS small-block V8 engine, introduced in 1997, was a clean-sheet design and shared only bore spacing with the predecessor SBC.
Starting in 1955 when it first started offering V8 engines, GMC relied on eight-cylinder engines from Pontiac, Chevrolet, and Oldsmobile, making this truly the earliest example of V8 engine sharing at GM, albeit in trucks and not cars. I guess GM figured truck buyers didn’t care as much as car buyers where their engines came from.
For most of its existence, GMC did not have its own gasoline V8 engine, save for a brief time from 1967 to 1972 when GMC sold an eight-cylinder version of their 60-degree V6/V12 engine. This massive, 637 cu. in. (10.4 liter) V8 engine weighed over 1,200 pounds. Alas, this bruiser was never fitted to any light-duty C/K series pickups – it was only available in larger commercial chassis and COE configurations. This is too bad because it could have been the Ram SRT-10 of its day.