1966 Full Size Pontiacs: What's the difference? Bonneville, Catalina and Grand Prix

Greg Zyla

Q: Hi Greg. As my love for my 1969 Firebird has faded, I found myself wanting a full sized 1966 Pontiac. The more reading I have done on the 1966 Bonneville, Catalina and Grand Prix the more confused I get. Visually they all appear basically the same. Can you break it down for me? Thanks, a Pontiac lover via email and sent by iPhone.
A: I’d be happy to as I receive few letters, emails or iPhone questions concerning full-size Pontiacs from 1966. First, and most important, is the fact that by 1966, almost all of the muscle car lovers, like you and me, were enjoying the new mid-size muscle cars ala Pontiac GTO, Chevy SS396, Fairlane GT, Comet Cyclone, Olds 442 and Buick GS to name a few. As for AMC, their mid-size performance cars were a few years away.
To make matters worse for the full-size performance cars that ruled from 1958 to 1964 were the new muscle performance “pony” cars, like the Plymouth Barracuda, Mustang 428 Cobra Jets, the Mustang Boss cars, Camaro Z28 and SS396, and your Firebird, which also came with some impressive performance engines.
Getting back to the full-size cars, Pontiac always enjoyed “Number One” classifications, thanks to dominating the races on the NASCAR ovals thanks to Smokey Yunick and Fireball Roberts and a bevy of other Pontiac drivers, including champion Joe Weatherly and the outstanding throttle man Junior Johnson. They all drove those full-size Pontiacs.
On the drag strips, drivers like “The Farmer” Arnie Beswick, Harold Ramsey in his Union Park Pontiac Catalina and Jim Wangers, who drove for Ace Wilson’s Royal Pontiacs, were top performers. They helped push the Pontiac brand especially with those SD (Super Duty) 421-inch, dual quad “Ponchos,” as they are known in the industry.
However good these full-size cars did on the tracks and as popular as they were on the nation’s boulevards, they just couldn’t compete with the mid-size and pony muscle cars, period.
Which brings us to 1966 and those full-size Pontiacs that still sold very well to the older crowd and family-oriented consumers. To answer your question, 1966 found numerous full-size Pontiacs available, from sedan to hardtop to convertible to station wagon.
The 1966 Pontiac was part of the third generation of Pontiacs (1965 to 1970), which featured an extended wheelbase from 120 to 121-inches, albeit a very minor extension. The bodies were heavier than the prior generation and the Catalina was still the entry-level Pontiac that year and for years to come. The engines available were the 389 and 421 V8s, and for the performance buffs, you could still order the tri-power 389. Although the standard Catalina engine was a 265-horse 389 two-barrel, a 421 High Output with tri-power was available on the Catalina 2+2 ultra performance model. So that pretty sums up the Catalina, which is the entry model. Notable here is that 1966 was the last year a consumer could order the tri-power, three two-barrel carb setup.
Also important is that even though there was a 1950 Catalina, it was not a standalone model and only denoted a hardtop version of the Chieftain Eight and DeLuxe Eight Pontiacs. In 1959, Catalina received its first standalone model designation as the entry-level full-size Pontiac.
The Bonneville, meanwhile, was more luxurious and was entering its fourth generation. The Bonneville appeared sooner than the Catalina, namely in 1958 and was always the most expensive of the full-size Pontiacs. The same engines that powered the Catalina were also offered in the Bonneville, which combined luxury and performance when powered by those tri-power engines. Most notable is that the Bonneville was different, as it rode on an extended 124-inch wheelbase versus the 121-inch Catalina.
The Grand Prix, meanwhile, was always a bit different as it rode on the Catalina’s smaller 121-inch wheelbase and tried over the years to merge the best of personal luxury with the best of performance. It debuted in 1962 on a 120-inch wheelbase with the choice of performance engines. Notable is that the popular 338-horse 389 tri-power was not available in 1966 on the Grand Prix, as the sole performance engine was the 421 with three deuces. Horsepower for the 421 HO was in at 376 horses, which was quite impressive. Other four-barrel engines were available, but a two-barrel engine was not in the mix as the Grand Prix nomenclature had to do with performance.
Of the three models, the Bonneville lasted the longest, selling all the way through the 2005 model year. The Grand Prix made it through the 2002 model year, while the Catalina’s final year was 1981. In my lifetime, I owned an “almost new” 1989 Pontiac Bonneville, and it was a reliable and fun car. However, the paint went bad in about one year from purchase. It was diamond dark red, and I remember many other cars having paint problems those years, too. I still have my 1994 Pontiac Trans-Am, and it only has 15,000 miles on it.
As you search for you 1966 full-size Poncho, remember that these cars are not worth the big money at the auctions like the mid-size and pony cars, but do command respect and dollars when equipped with the performance engines. Good luck in your search for your Pontiac.

Facebook Twitter
View Count 12,064