Thanks Ted. It is definitely an open rear end. 3.00 ratio. Gave $220 for it. Gears look fine. If it runs quiet I don't think I got hurt too bad on it for that price. I have a '65 Mustang coupe rat rod project that it will make a good street gear. It has a mild 302 with a C4 and a 2.88 8" in it now. I have a spare '57 wagon housing that I plan to use. It will smoke the tires with the 2.88. The 3.00 should be a little better. Going to have a mechanic friend build a 3.89 Tracton Lock from another spare center section that I have with a noisy 4.56 gear set. That's going to be my short haul street gear.

I went through my collection of 9” housings and as a general rule the limited slip carriers use 5/8” headed bolts and the open carriers use ¾” headed bolts.  I do remember exceptions to this where 5/8” bolts have been used on open carriers but I do not recall of any instances where ¾” bolts were used on limited slip carriers.  All Ford 9” Traction Loks I have dealt with have recessed or countersunk bolt holes for the ring gear carrier bolts which necessitates using 5/8” headed bolts.
 
Without any pictures to show you the external differences on the carriers, the easiest way to identify the Traction-Lok from an open carrier is to look inside the carrier on the drivers’ side where the axle goes in.  The left side (drivers’ side in U.S.A.) of the Traction Lock carrier will have a double row of teeth for the axle to go into.  If just looking at the axle for that side, you’ll see a parting line around the splines where that double row of teeth is within the carrier assuming that axle had been used in a limited slip carrier.  An axle used within an open carrier will not exhibit that trait.

Lorena, Texas (South of Waco)

That helps. Next question. Are all 9" center sections with 5/8 bolts traction locks? I have one with 5/8 bolts that I was sold as a traction lock but after doing some research I see that the bolts are supposed to be recessed on a traction lock and they aren't. I'm thinking its not traction lock. Thinking I blew it since I bought it for the traction lock. Traction lock or not?

The yokes and front pinion supports are ‘physically’ interchangeable.  There is a crush sleeve located between the two pinion bearings that should be replaced each time the yoke is loosened up and retightened.  The solid sleeve style bearing spacer or non-collapsible sleeve that comes in the nodular 9” units allows the yokes to be changed out without having to contend with the collapsible crush sleeve.
 
The pinion support gets more complicated though.  The pinion depth itself may have to be readjusted through the use of different size support shims when moving pinion supports from one housing to another.  On a used ring and pinion set where the wear pattern has taken a ‘set’, then getting the pinion depth back to its original location becomes critical.

Lorena, Texas (South of Waco)

I have two 28 spline center sections. Are the yolks and bearing retainers interchangeable?