rebuilt 3rd member

[jtschug]

Yep, that curved rib confirms it is a 9.375” ring gear with 31 spline axles.

A 9” third member with 31 spine differential will bolt in.

[sleeper bird]

Thanks and i appreciate the heads up about johns.just for my knowledge was that rib for extra strengthening of the larger ring gear?im just curious.and is the yolk a 1330 style?

[jtschug]

I don't know why the extra rib is there. Clearly when Ford designed the 9.375 ring gear, they expected it to be stronger than the 9". They installed them in heavier vehicles with bigger engines, like all the Lincolns and the 428, but not 390 Thunderbirds. They also put them in the heavy duty pickups.

However, experience at the drag strip tells a different story. The bigger ring gear moved the pinion down a little bit lower on the case, and this revealed itself to be a weak point. With wide slicks and stout axles and a big engine when the 9.375 was put to the ultimate stress test, they tended to eject the pinion more often than the 9" with a nodular iron case. Thus the Ford 9" became the standard drag race rear axle, even in Chebbies.

[sleeper bird]

Thanks for that information it was very helpful again i appreciate all the help.