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Automatic Transmissions
Pontiac V8 Automatic Transmissions
Behind a Pontiac, Not a Chevy — Automatic Transmissions for Pontiac V8s
An automatic transmission swap on a Pontiac is straightforward as long as you respect the two things that come with it: the flexplate has to match the engine's balance, and the torque converter has to match the camshaft and the rear gear. The transmission itself is often the least complicated part of the order.
Butler carries TCI TH400 units built on the Pontiac BOP pattern, competition TH400s with manual valve bodies and trans brakes, electronic 4L80E-based overdrives, and complete overdrive kits from CPT and SST.
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1. Keeping the TH400
There is nothing wrong with a Turbo 400 behind a big-torque Pontiac, and it remains the simplest strong answer.
| Street TH400 | TCI builds a TH400 on the B.O.P. pattern, non lock-up, with a 4" tail shaft. It bolts to a Pontiac block without an adapter. |
| Competition TH400 | a Super Street Fighter competition unit with a 4" tail shaft and no trans brake, for a car that still has to drive. |
| Manual valve body | TCI offers TH400s with a manual valve body and reverse shift pattern, with and without a trans brake. A reverse pattern manual valve body is a race decision, not a street one. |
| What it costs you | no overdrive. Behind a 3.55 or steeper rear gear, a TH400 car is busy on the highway. |
2. Overdrive options
| CPT TH-200-4R kit | rated for 700 horsepower and, importantly, it bolts directly to Pontiac blocks with no adapter plate. Gear ratios are 2.74, 1.57, 1.00 and 0.67. The kit ships with the transmission, TV cable and bracket, yoke, BOP dipstick and tube, and a converter, and CPT backs it with a 3-year, 30,000-mile limited warranty. |
| SST A41 | an aftermarket replacement for the GM 4L60E and 4L65E, offered in Stage 1 at 450, Stage 2 at 550 and Stage 3 at 650 torque. Ratios are 3.06, 1.63, 1.00 and 0.70, and SST states it offers a 30 percent reduction in cruising rpm with no tunnel cutting. Note that it requires a QuickTime adapter bellhousing to go from Buick-Olds-Pontiac to the A41. |
| Electronic four and six speed | TCI builds 4L80E-based units, including a six-speed package with ratios of 2.97, 2.23, 1.57, 1.18, 1.00 and 0.75, rated to handle up to 850 horsepower, supplied with the EZ-TCU controller and harness, dipstick, cooler and fluid. |
3. What the swap actually demands
This is the part that surprises people who priced only the transmission.
| Flexplate matched to balance | Butler's flexplates come in neutral (internal) and stock (external) balance and must match how your engine was balanced. A Butler-built rotating assembly is neutral balanced unless you were told otherwise. |
| Converter matched to the combination | stall speed depends on engine size, torque, car weight, rear gear and power adders. Some higher-stall converters also require the flexplate to be drilled for 7/16" bolts. |
| Cooling | an auxiliary cooler is specified for the higher stages of the SST A41 and is offered as an option on the CPT kit. An overdrive automatic behind a 455 makes heat. |
| Control and speedometer | a 200-4R needs its TV cable set up correctly or it will destroy itself. An electronic unit needs its controller. A speedometer correction adapter is available for cars whose indicated speed is off after the swap. |
| Crossmember and mount | the SST kit includes a heavy duty formed steel crossmember and an isolator by car application. A bare transmission does not. |
Call the shop with the engine's balance method, the cam, the rear gear and the car's weight before ordering. That conversation sets the converter, and the converter is what you will actually feel every time you drive the car.
Not sure what your Pontiac needs?
Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.