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Founder, 1929-2014
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Flathead V8 to Ford C4 Transmission Basic Adapter Kit

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Flathead V8 to Ford C4 Transmission Basic Adapter Kit

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Please NOTE the following about this product:

  • This item is sold as a kit.



Q & A

What's in the Box

If you have access to your own transmission and parts or you wish to adapt an AOD, Ford C-4 or Ford C-6, this basic adapter set is what you need. Includes: starter nose cone, flexplate, bellhousing adapter and instructions. Choice of 157 or 164 flexplate. Use with 302-351W transmission. For Ford C4 and Ford C6 transmission application.

916-28901 Instructions (pdf)


This kit uses C-4 transmissions from 1966-76 Ford passenger cars, vans and pickups with 289-302-351W V-8's and 250 6-cylinder engines. 

  • If the bolt pattern on the front of the torque converter is a 10-1/2" circle, order the 157 tooth version. 
  • If the bolt pattern on the front of the torque converter measures 11-1/2", order the 164 tooth version. 

Item Details

Basic Hardware Only: Starter Nose Cone, Flexplate, Bellhousing Adapter, Instructions

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Ford C4-Ford C6 Transmission Cushions
(Part #91018017)

The studs on the Ford C4 or Ford C6 tranny mount are 10mm x 1.5 thread. It is a standard replacement mount that fits most Fords and is not uncommon, as metric fasteners have been used on domestic vehicles for over 25 years. For Ford C4 and Ford C6 application.

The slots in the crossmember will require a little grinding to use this mount.

ARP Fasteners 200-2902 Chevy Flexplate Bolts
(Part #1012002902)

Flexplate bolts play an important role in the performance and safety of race cars and street machines alike. That’s why the fastener experts at ARP develop special bolts that are far superior to OEM hardware. Forged from aerospace alloy and heat-treated prior to thread rolling and machining.

Fits Chevrolet 90° V6 & 265-454 Chevy V8 with 2-Pc rear seal. Set of 6 bolts.

  • Exclusive, flat, 12-point head design
  • Larger than stock shank diameter for increased strength and improved flexplate register
  • Originally developed for NASCAR Winston Cup competition
  • 200,000 psi rating
Flathead V8 to Ford C4 Auto Transmission Conversion Kit
(Part #91028906)

Adapt your 1949-1953 Ford flathead V8 engine to a modern Ford C4 automatic transmission. This complete C4 transmission conversion kit is an excellent upgrade for early Ford drivetrains – the lightweight flexplate and torque converter does wonders for a flathead's throttle response and stop-and-go driving. This kit includes Speedway's Street King Ford transmission completely remanufactured with heavy duty clutches, special shift kit, torque converter, engine adapter, special flexplate, modified 12-volt starter, hardware, and instructions.

  • For Ford C4 transmission application
  • Handles up to 550 HP
  • 2200-2600 rpm stall torque converter
  • Firm, crisp shifts from Kevlar bands and H.D. clutches
  • Street/Strip Valve Body - everyday street driving and weekend trips to the drag strip
  • Billet 6061 T6 Aluminum Pro Shift Servo - extends clutch and band life
  • Improved Lubrication Circuits - reduced heat/prolonged life
  • Chrome steel transmission pan
  • Transmission has a one year warranty

Note: Must be used with open drive rearend (not included). Cooler, shifter, and chrome dress-up parts are sold separately. Fill tube, dipstick and kickdown cable are included. Also, the 6 gear planet is NOT used in this transmission.

910-28906 Instructions (PDF)

Ford C4 Transmission Drive Shaft Slip Yoke
(Part #80292440)

This Ford C-4 driveshaft slip yoke measures 6.5" from the center of the U-joint cup to the front end of the yoke. Fits transmissions with 28 spline tailshafts. Accepts 1310 style U-joints (popular Chevy) with 1-1/16" cups and a spread of 3-7/32".


Note: Due to the length of the yoke, it will fit C4 transmissions ONLY, and is not recommended for use on an AOD transmission. The expressed measurement or length of the slip yoke is taken from the center of the u-joint to tip, not overall.

Tremec GM TKO 5-Speed to 1949-53 Ford Flathead Engine Conversion Kit
(Part #91028908)

This all-in-one kit is designed to adapt the versatile TREMEC TKO-500 transmission to your 1949-53 Ford Flathead engine. Serving up 500 lb-ft of torque capacity, along with confidence-inspiring shifts and fuel-saving overdrive, the TKO offers an ideal blend of brute strength and street manners. This kit includes everything you need for installation*.

  • Sold as a complete conversion kit
  • TKO overdrive transmission to 1949-53 Flathead
  • .68 overdrive 5th gear for smooth cruising on the highway
  • *See note below regarding 1949-53 OEM 3" adapter

Kit Includes:

  • TREMEC GM TK-500 5-speed overdrive manual transmission (91029027)
  • GM Manual Transmission to Flathead V8 adapter (91628912)
  • Flathead clutch release bearing (91025620)
  • Release bearing adapter (91629517)
  • Pilot bearing (91629520)
  • Flathead 10-1/2" long style clutch pressure plate 910-15635
  • Flathead 10" clutch disc (91015644)
  • Flathead clutch release fork (91675150)
  • Flathead clutch shaft release pin (91675151)
  • Flathead clutch release shaft (91675101)
  • Clutch release spring (91675152)
  • Flathead steel flywheel (91015629)
  • ARP flywheel bolts (1012002802)
  • ARP pressure plate bolts (1011502201)

Note:  Flywheel provided in this kit is for the 1949-53 Ford Flathead engine application. The 1949-53 engine application will require this kit to utilize the OEM 3" adapter bellhousing (to be provided by the installer - not currently available from Speedway Motors).

TKO-500 Illustrated Parts Manual (PDF)

TKO-500 Service Manual (PDF)

TKO-500 Installation Tips (PDF)

916-28912 Instructions (PDF) 

Starter 49 FH Ford/C4 Auto
(Part #91067449)
Powermaster 9603 Small Block Ford Gear Reduction Starter, A/T
(Part #91067462)

Powermaster's MasterTorque Series gear reduction starters have a 1.4 Kw motor that cranks out 180 ft.-lbs. of torque. Fits Small Block Ford 289-302-351 with an automatic transmission or 5-speed manual transmission. Also works well with Speedway Flathead-to-C4 Automatic Conversion (910-28906).

  • Five Position Indexing
  • No Heat Soak Problems
  • Clears Oil Pans if OE Starter Fits
  • Billet Aluminum Adapter Block
  • 4.4:1 Gear Reduction Ratio
  • Power for up to 12:1 Compression
  • Mounting Bolts Included
  • Dyno Test Results Included
  • Weight: 10.5 lbs.
Powermaster Tech Bulletin (PDF)

910-67462 Instructions (PDF)