Pontiac LeMans 1968-72 G3

Pontiac’s 326 was actually a 336 and the 350 that replaced it in 1968 was really a 354.74, which nobody at the division ever adequately explained. The G3 LeMans carried that engine through some of the best years of the A-body, picked up big valve Ram Air heads for 1969, and by 1970 could be ordered with GTO-sized engines in a cheaper package. Read on for the LeMans years worth knowing, including the budget hardtop Chevrolet undercut within weeks.

Here is a puzzle nobody at Pontiac ever bothered to solve in public. The division sold an engine badged as a 326 that actually displaced roughly 336 cubic inches. It replaced that engine with one badged as a 350 that actually displaced 354.74. Neither number was accurate, neither error was in the direction that would have flattered the product, and no satisfying explanation has ever emerged for why a company that obsessed over performance imagery would round its own displacement figures downward. That quirk sits at the center of the mid-size Pontiac story during some of the best years the A-body ever had, and it is a useful reminder that badge numbers are marketing rather than measurement.

The Displacement Numbers Pontiac Simply Made Up

There is at least a partial explanation for the 326, and it involves corporate rulemaking rather than sloppiness. When Pontiac introduced the engine for 1963 it genuinely displaced about 336 cubic inches, and it was badged as a 326 because General Motors had imposed a displacement ceiling on its intermediate cars that a 336 would have violated. For 1964 Pontiac reduced the bore slightly so the engine actually measured close to its badge, which is the only instance anyone can point to of a manufacturer making an engine smaller in order to tell the truth about it. The 350 that followed had no such excuse. Pontiac simply arrived at 354.74 cubic inches through the bore and stroke combination it wanted, then rounded down to a familiar round number and moved on.

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Five Body Styles on the A-Body Platform

The third generation LeMans, launched for 1968, rode on General Motors’ A-body platform, shared with the Tempest and with corporate cousins from Chevrolet, Oldsmobile and Buick. Pontiac offered it in five body styles: a two-door coupe, a convertible, a four-door sedan, a two-door sedan and a four-door station wagon. That breadth is worth pausing on, because it reflects an era when a single nameplate was expected to cover a family hauler and a stoplight brawler with the same badge on the fender. The two-door and four-door cars used different wheelbases, with the shorter chassis under the coupes giving them the proportions enthusiasts remember.

How a 326 Became a 350 Without Being Either

The engine swap for 1968 is where the arithmetic gets interesting. Pontiac took the existing 326 architecture and simply bored it out, going from 3.72 inches to 3.88 inches while leaving the 3.75 inch stroke exactly where it was, producing the 354.74 cubic inches that everyone agreed to call a 350. Buyers could have it with a two barrel carburetor producing 260 horsepower, 193.9 kW, or with a four barrel developing 325 horsepower. The four barrel version in particular was a genuinely quick engine in a car that did not advertise it, which is the most appealing kind.

1969 and the Last Good Pontiac 350

For 1969 Pontiac reworked the engine with a new camshaft and fitted number 48 big valve heads, the same casting used on the Ram Air III. Output rose to 265 horsepower, 197.6 kW, for the two barrel and 330 horsepower, 246 kW, for the four barrel. This is the high water mark and it did not last: 1969 was the final year a high performance version of the Pontiac 350 appeared on the option sheet at all. Anyone hunting a LeMans for the engine rather than the badge should be looking at this specific year, and should be checking head castings rather than trusting a fender emblem.

The 1970 Reshuffle That Demoted the Base Car

A revision to the mid-size lineup for 1970 shuffled the hierarchy. The base LeMans was downgraded to replace the Tempest Custom, offered as a two-door or four-door pillared sedan, while the LeMans Sport carried on in all the body styles previously offered. On paper this reads like a demotion, and in marketing terms it was. In practice it created something more interesting, because the cheaper cars became eligible for equipment that had previously been reserved for their expensive siblings.

GTO Engines in a Cheaper Wrapper

That is the important part. Beginning in 1970, engines that had generally been kept for the GTO became available in the lesser LeMans and even the Tempest. A 400 cubic inch, 6.55 liter V8 joined the roster, producing 265 horsepower, 197.6 kW, with a two barrel or 330 horsepower, 246 kW, with the optional four barrel and dual exhaust. A buyer paying attention could put a big Pontiac engine into a plain body without the GTO’s price, insurance profile or attention from law enforcement. That is the classic sleeper recipe, and it was sitting on the order form.

The GT-37 and the Chevelle That Beat It by Weeks

Later in 1970 Pontiac formalized the idea with the GT-37, a budget priced hardtop coupe that the division promoted as the lowest cost hardtop available from General Motors. The claim held for a matter of weeks before Chevrolet duplicated the concept with a Chevelle at a lower price, which tells you something about how closely the divisions watched each other. As an option package for the LeMans or Tempest, the GT-37 added a three-speed floor shift, tuned suspension, striping and trim aimed squarely at buyers who wanted the look and the handling without the full performance-model price.

Why the Lesser LeMans Is the Smart Buy Now

All of which makes the ordinary LeMans an unusually sensible thing to buy today. GTO prices have long since separated from the rest of the A-body world, while a LeMans or LeMans Sport in the same body with the same sheet metal costs a fraction of the money and rewards exactly the same restoration effort. A 1969 car with the 330 horsepower four barrel and the number 48 heads is the enthusiast’s pick. A 1970 or 1971 car ordered with a 400 is the sleeper. Verify with the PHS documentation service, which for Pontiac owners remains one of the best factory records resources in the hobby. Share your thoughts in the comments below.

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