Adapting Your T5
The T5 transmission in this '33 coupe uses a GM manual trans to Flathead V-8 adapter/Ford clutch from Speedway Motors (PN 916-28912). This adapter is one of several Speedway adapter styles available for this application.
1. The Speedway 916-28912 adapter allows you to retain your Ford clutch release shaft, arm, fork, and bearing. It's a great choice for applications like this '33, where an original-style chassis and pedals are being used.
2. This is the same adapter with the components assembled.
3. Compare the 916-28912 adapter (right) to PN 916-28914 (left), which is designed for the same Flathead-to-T5 application, but for use with a GM-style pressure plate and release fork.
4. The 916-28914 GM-style adapter (right) features a large clutch fork window instead of the small hole on the 916-28912 Ford-style adapter.
5. The 916-28914 adapter can be used with Speedway's GM-style clutch fork and release bearing assembly shown on the left (PN 916-29510) or the hydraulic throwout bearing assembly on the right (PN 910-25610). The hydraulic throwout bearing has the advantage of not requiring a mechanical means for releasing the clutch. A clutch master cylinder at the pedal, and hydraulic lines routed to the throwout bearing, can be used.
6-7. In photo 6, the clutch fork and mechanical release bearing assembly are being installed in a GM-style adapter mounted on a T5. In photo 7, the hydraulic throwout bearing and release bearing spacer are being installed.
8. An adapter sleeve is installed on the T5 input shaft for any of these T5 to Flathead conversions, or Speedway can supply an adapter pilot bearing (PN 916-29520), which eliminates the need for the pilot bearing sleeve.
9. Flywheel choice depends on which adapter and which clutch and release assembly is being used. When using the GM-style adapter, the stock Flathead flywheel must be re-drilled to accept the GM-style diaphragm pressure plate. The alternative is to replace it with a Speedway flywheel that has the GM pressure plate pattern. This flywheel (PN 910-15629) will accept stock Ford- or GM-style pressure plates.
10. This 10-1/2-inch GM-style diaphragm pressure plate (PN 910-15637) and clutch disc are bolted to the flywheel. In addition to matching the flywheel and pressure plate, the clutch disc must match the transmission's input shaft spline count (14 spline on the NWC S-10-style T5, 26 spline on the WC Camaro-style T5).
11. On early Flatheads, the bellhousing was cast into the block. After 1948, Ford used a separate bellhousing. Using Speedway's 916-28912 or 916-28914 adapter on a later Flathead requires the use of either a cast-iron Ford bellhousing from a '48-52 pickup application, or a stamped steel '49-50 Mercury bellhousing (as shown here). A matching starter plate or cover assembly is also required for mounting the starter and protecting the flywheel.