Engine and Transmission Tech

5L SBF, redrilled to fit 6 bolt RV8 pattern ? 19lb. ductile iron, 11" clutch, 157 tooth, $99. new, ebay.
Maybe ? Art.

I've no idea what this is, but I'm going to assume a $99 flywheel is iron. Don't the Fords also have a large lump in the flywheel as part of the balancing?
I purchased the steel unit from TS Automotive. Came in a Mcleod box, and a very nice piece of kit. Currently $330 but I paid $270 on eBay a few years ago. I just can't bring myself to use lightened iron flywheels in any of my modified vehicles.

FYI, the SBF used three different flexplate/flywheel sizes: 148, 157, and 164 teeth. The 148 teeth flexplates are comparatively rare, having been used in cars like the V8 Mustang II. 157 teeth were generally used in 289/302 small and mid-sized cars, while the 164 teeth flexplates were used in 289/302 full-size cars and 351W/351C applications. Only the 164 teeth were drilled for 11" pressure plates (Long style). The V8 Foxbody Mustangs used 10" clutches from 1979-1983. 1984-up SBF Mustangs used 157 teeth flywheels drilled for 10.5" diaphragm pressure plates.

I've got 157 and 164 teeth SBF flywheels here as well as Buick/Rover so can compare if someone needs me to.

> Don't the Fords also have a large lump in the flywheel as part of the balancing?

Depends upon the flywheel. Some are neutral balance and come with bolt on balance weights. There was a balance factor change in 1981. Earlier SBF engines were 28.2 oz-in, as are all 351W and 351C/351M/400. Later 5.0L/302 cranks were lightened which required additional mass added to the harmonic balancer and flywheel/flexplate. 1981-up 5.0L/302 engines have a 50 oz-in balance factor. The Ford 300 inline 6 used in trucks has the same crank bolt pattern as the SBF but uses internally balanced flywheels (164 teeth).

Thanks, Dan!

Wow, great info Dan! Thanks!