Thread: what is this FORD rear end called?

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Originally Posted by Dave Severson

If it is the 9 3/8", they do fit into the standard 9" housing, might have to grind a bit on the housing for the ring gear to clear, but that's about it.

I think all you have to do is grind a relief the gasket flange of a 9" housing to fit a 9-3/8 ring gear(or so I've been told) I also think the 9-3/8 are all 31 spline, but, again, don't know from experience, only hearsay.

My recollection is that most of the 9-3/8 gear ratios 'suck', i.e. 2.56/2.69 or thereabouts. Great for prairie cruising/economy behind a C6 in your 429/460 powered Town Car or Thunderbird but not much for performance

Originally Posted by IC2

I think all you have to do is grind a relief the gasket flange of a 9" housing to fit a 9-3/8 ring gear(or so I've been told) I also think the 9-3/8 are all 31 spline, but, again, don't know from experience, only hearsay.

My recollection is that most of the 9-3/8 gear ratios 'suck', i.e. 2.56/2.69 or thereabouts. Great for prairie cruising/economy behind a C6 in your 429/460 powered Town Car or Thunderbird but not much for performance

I found a good use for one of the center sections, anyway... It's the one I use for mockup on builds, and when I narrow housings!!!! The aftermarket now has some very good ratio's in 9.5" ring gears, but they're made for aftermarket center sections. They are a bit stronger when you start getting into the 1,000 + horsepower builds, might be a consideration. But yeah, the factory 9 3/8" certainly isn't anything to write home about, especially with all the good parts available for a reasonable price thru the aftermarket suppliers...