Pontiac came out with tripower in 1957 and produced them until 1966. In 1957 and 1958, the 3 Rochester carbs were all the small based version. Starting in 1959, the end carbs used were the larger based units, while the center carb remained small. The final year, 1966, Pontiac used 3 large units.
The intakes from '57 and '58 do not have casting numbers. The only real difference is the size of the heater hose outlet. There's not much demand for these intakes. Many people refer to the tripower intakes from 57-63 as "boat anchors". Pictured below is a 1958 tripower. Jon Havens contributed this picture.
The '59 and '60 intakes are similar, but unique. The '60 has water bypass built into the waterneck. Part #1959 is 532422. Part number #1960 is 536194.
The '61-'63 intakes are virtually the same and interchangeable. The '61 intake is Part #1961 is #538202. 1962 is #541690. and, 1963 is #9770275. Pontiac also made an aluminum tripower intake in 61. As far as I know, it was only available over-the-counter at Pontiac dealerships. It is known as the Super Duty 61 Intake. Part number is 540510. A web page visitor, Terry Merrifield pointed out that all these intakes may have had same casting date...B41...Feb 4th, 1961.
Pictured below is a 1961 Pontiac vacuum tripower. Note the routing of the fuel lines.
Between 61 and 64, the choke tubes enter a special "plate" bolted to the intake. The '64 intake is very much like the '61-'63 and will bolt onto the '61-'64 heads. However, the carbs sit higher and are sometimes referred to as "high rise tripower". If you have a '64 GTO, get the '64 intake. They are not that pricey. Part # 9775088.
Below is a 1964 tripower I did for a customer. Note that the casting under the front carb is taller than the 61 to 63 as pictured above.
None of the intakes from '57 to '64 will fit the '65 up heads. As a result, demand for them is much less. The '65 and '66 intake are different in several ways, but either will fit the newer heads.
Also, while on the subject, after-market companies, (two that I am aware of) are making an intake for the 66 tripower. One is made in China and the other cast, I believe, in Texas. Quality varies. I would like any feedback from people who have bought them. I will share that with visitors to the page.
Aluminum tripower intakes were made to fit '64 and earlier heads. Some even have 3 bolt carb flanges for the old Stromberg carbs. Some accept three small Rochesters, like the 57-58 Pontiac, the old 348s and J-2s. They would be interesting on a nostalgia street rod, but not on your muscle car. I can build one for you, if you are interested.
The '65 intake has 2 choke tubes on the crossover that go directly into the manifold. It still has the smaller center carb. Casting # 9778818. Both 65 and 66 intakes are attached to the heads with 10 bolts. See the picture of a finised unit below.
The '66 intake has a completely different choke mechanism. A box with a coiled spring is bolted to the passenger side of intake with one bolt. It is a special Phillips head bolt (sold under ). A rod from the stove attaches to the end of the choke shaft. The '66 intake has 3 large based Rochester carbs. Part #9782898. See pic.