Transmission & Drivetrain
Pontiac V8 Transmission & Drivetrain
Behind the Flywheel — Transmission & Drivetrain for Pontiac V8s
Everything behind the flywheel has to survive what the engine in front of it makes, and Transmission & Drivetrain is where that handoff happens on a Pontiac V8. Whether you are putting a factory four-speed back behind a rebuilt 400 or bolting a Tremec five-speed to a stroker, the bellhousing, the clutch or converter, and the flywheel or flexplate all have to agree on bolt pattern, tooth count, register bore and balance.
Butler stocks Pontiac bellhousings from American Powertrain, Lakewood, QuickTime and SST, clutches from Centerforce, RAM and American Powertrain, SFI flywheels and BP Series flexplates, TCI torque converters and TH400 automatics, plus complete Tremec TKX and Magnum conversion kits from SST and American Powertrain.
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1. Bellhousings: the pattern that starts it all
The bellhousing is the first decision in a manual driveline, because it sets what transmission you can run and what clutch will fit inside it. Butler carries factory-style castings and SFI-certified safety bells.
| OE-style aluminum | The American Powertrain BOP bell is cast from thick-wall, high titanium content aluminum alloy, CNC machined for parallelism and pre-checked for concentricity to factory specs. It has dual starter pockets, works with factory BOP flywheels and mechanical linkage, and accepts a Muncie, Super T10, GM TKO, GM LGT700 or GM Richmond. Order it with the factory-spec steel inspection cover or reuse your original. |
| Heavy cast replacement | The SST Pontiac bellhousing is made in the USA as a heavy casting, unlike the originals, and includes an inspection cover. |
| SFI safety bells | The Lakewood blow-proof bell is SFI 6.1 certified, fits 1964 to 1981 Pontiac 326 to 455 with mechanical linkage and an 11 in. clutch, works with Muncie, BW-T10 and Tremec TKO, and includes a block plate and Grade 8 hardware. QuickTime steel bells are SFI 6.1 as well, one for Muncie, Richmond, Saginaw, BW-T10, Jerico and TKO 500/600, and one that puts an LS-pattern T56 or GM Magnum behind a Pontiac V8. Both use a 166-tooth flywheel and an 11 in. disc. |
| Dowel pins | Extra-long bellhousing dowel pins from Butler, TCI and Moroso make lining up a heavy bell far easier, and the Moroso pins are offset .021 in. to correct a bore that is out of location. |
2. Clutches, flywheels and release parts
Clutch selection comes down to torque, diameter, spline count and how the car gets driven. Butler stocks both street-friendly and hard-launch packages.
| Centerforce Dual Friction | Available in 10.4 in. and 11 in., in 1-1/8 in. 10-spline and 26-spline, with a full facing on the pressure plate side for drivability and a segmented carbon composite facing on the flywheel side for holding power. Torque ratings run up to 525, 590 and 620 ft-lbs depending on the kit. Note from Centerforce: these will not work with a McLeod hydraulic throwout bearing. |
| RAM Powergrip | Diaphragm sets with an 8-spring hub in 10.5 in. and 11 in., 10- and 26-spline, rated for applications up to 550 hp, and supplied with pressure plate, disc, release bearing and alignment tool. |
| American Powertrain Duo | The Mean Street Duo is rated 450 to 580 ft-lbs for mixed street and strip or pure street. The Track Slayer Duo is a 6-puck ceramic setup rated 645 to 800 ft-lbs, meant for the drag strip and the drive back to the trailer. Both include pressure plate, disc, alignment tool, pilot bearing and release bearing. |
| Flywheels | Butler True Balance billet steel, RAM billet steel, American Powertrain billet steel and aluminum, Centerforce and PRW 30 lb. steel. The common Pontiac spec is 166 tooth with a 2.750 in. register bore and both 10.5 in. and 11 in. clutch bolt patterns for 1964-76 326-455. |
| Small parts | Pilot bearings and bushings, including a standard bearing, an oversized bearing for a worn crank snout, a bronze oil-impregnated bushing that may need fitting to your crank for proper press fit, and one that installs in the torque converter hub hole when you run a mid-plate. The Butler Clutch Install Kit bundles pilot bearing, thrust bearing and pressure plate bolts. |
3. Internal versus external balance: get this wrong and nothing else matters
This is the single most common mistake on a Pontiac driveline order, and it costs people a teardown.
| What the factory did | Pontiac balanced its cranks using an external, or stock, balance method. That called for an offset weighted flexplate or flywheel, sometimes with holes drilled to lighten one side, sometimes with an additional weight bolted on to add it. |
| What shops do now | Butler and most shops internally, or neutrally, balance crankshafts. A neutral-balance engine uses a flexplate or flywheel with no offset holes and no added weights. |
| So order to your crank, not your year | Butler stocks both versions across most families carried, including BP Series, PRW, ATI, Hays, Meziere and TCI flexplates and Butler, RAM, American Powertrain, Centerforce and PRW flywheels. |
| Hub diameter | Register bore matters too. Most performance pieces use a 2.75 in. center. If your crank has a 2.5 in. hub, Butler makes a spacer ring to adapt it, and there is a second ring for a 2-9/16 in. hub. There is also a stock-replacement external-balance flexplate for 1975-79 with the 2.50 in. center. |
4. Automatics: flexplates, converters and transmissions
On the automatic side the converter is the tuning knob, and the flexplate is the part that quietly fails when the converter gets aggressive.
| BP Series flexplates | SFI 29.1 certified, 166 tooth, 2.75 in. center, roughly 40 percent thicker than a stock flexplate, rated to 12,500 rpm, precision balanced and double-welded at the ring gear. Bolt patterns for TH400, TH350 and 700R4 are all included, in both stock and neutral balance. |
| Torque converters | TCI units from 9 in. through 12 in., with anti-ballooning plates, in stall ranges that cover a mild street combination up through a serious bracket car, plus nitrous-specific and Pro-X pieces. California Performance Transmission offers TH-200-4R converters in single and dual pattern. |
| Transmissions | TCI TH400 B.O.P. units, including a non lock-up with a 4 in. tail shaft, a Super Street Fighter competition version, and manual valve body reverse-pattern builds with or without a trans brake. TCI also offers the 4x electronic 4L80-E and 6X six-speed packages with a Pontiac bellhousing. For overdrive, CPT builds a complete TH-200-4R kit and SST offers an A41 four-speed automatic PerfectFit kit with the Lakewood bellhousing included. |
| Speedometer | Plan for it up front with the TCI speedometer control unit or the CPT speedo correction adaptor. |
5. Tremec conversions: pick the kit that matches your body and your starting point
A five- or six-speed swap is the most popular drivetrain upgrade on an older Pontiac, and the kits are organized by body and by what is in the car today.
| SST Perfect-Fit TKX kits | Built for specific Pontiac bodies, and offered in two versions for each: manual-to-TKX and auto-to-TKX. Coverage includes 58-64 and 65-70 B-body, 62-64, 65-67 and 68-74 X-body, 64-67, 68-72 and 73-77 GTO and LeMans A-body, and 67-69 and 70-81 F-body. |
| American Powertrain TKX kits | A-body 1964-67, A-body 1968-72 BOP, and F-body 1967-69, 1970-74 and 1975-81. |
| Bare transmissions | Building your own package? Butler sells the Tremec TKX five-speed and the Magnum T56 six-speed, close ratio and wide ratio, as transmission-only. |
| Hydraulic clutch actuation | The American Powertrain HYDRAMAX system is built for the TKO, and SST offers a hydraulic actuator for TKO, TKX and Magnum. American Powertrain specifically recommends HYDRAMAX with their Duo clutch kits. |
6. Linkage, mounts and fluid
The parts that keep a mechanical clutch working are still reproduced, and they are body- and year-specific.
| Z-bars and forks | Z-bars for 1964-66 and 1968-72 A-body, clutch forks and boots for 1964-77 Pontiac V8, fork push rods, and clutch springs for 1964-65 and 1966-67. |
| Pivot studs | These are the ones people order wrong. Butler lists Z-bar-to-engine studs for 1964-67 and 1973-77 A-body, 1967-69 F-body and 1970-81 F-body, a Z-bar-to-frame stud for 1964-77, and a separate stud that threads into the bellhousing. |
| Mounts | The transmission mount comes in rubber for a stock-feeling street car and polyurethane where you want less driveline movement. |
| Fluid | Driven AT3 synthetic racing automatic transmission fluid, and Driven STF synthetic synchromesh fluid for manual gearboxes that call for it. |
If you are not sure what fits, work in order: crank balance first, then flywheel or flexplate, then clutch or converter, then bellhousing and transmission. Get those four right and the rest is hardware. Call the Butler tech line before you order if your combination is unusual.
Flexplates (Automatic) Clutches Transmissions Bellhousings Torque Converters Flywheels (Manual)
Not sure what your Pontiac needs?
Email our tech team at tech@butlerperformance.com. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.