The data plate indicates a 3:50 open,
although I don’t believe it’s original to the Kar. It is a June built Dearborn Kar, the pinion support is 5B15 an the third member is 5B2 an I think it’s an Trac Loc Posi. so no way original to the Kar. When machinist was working on engine he thought the Kar was used for drag racing, it had triple valve springs an some other modifications according to him. This may account for the Trac-Loc, but the number 9 in the housing is still a mystery.
Relicdog