Doesn't look like it. Here's a picture of a stock one It measures 5 inches to the end of the threads.
5.5in. I think is norm, @ least for 1948 sq. back,that I just did. The way your showing to outer tip. Lets some others input.
I get 5 & 7/16” OAL, the thread is 15/16” in length and the .750 inner bearing diameter is 13/16” in length.
My spare round backs are 5-7/16 as well. Yours appears to have a extra hole in board between the 2 mounting holes which ive never seen. Whats the back look like? Could it be a F1 spindle, or a Lincoln,or a Ford tractor?
Here’s a sketch of a Model A spindle that shows the modifications necessary to adapt Model T hubs from T wooden wheels. The wood spoke wheels had hubs with six bolt holes, not lug bolts, but bolts to hold the hub to the spokes. The six lug hubs were popular on early oval track cars. I’m not sure but the dimensions on the spindle that @DG Racing posted look like they could match.
Those look an awful lot like they have been modified for 49 to 54 chevy hubs and brakes. I've seen it done a few times. never could understand why anyone would want that but I have seen it.
Yeah I should have used a better ruler. I used an old drafting ruler and didn't think about the seal area. The ruler is 1/2 inch longer... so 5.5 inch. DOH! Those spindles I have are bone stock round back spindles.
ok my father ad a jobber spindle 1940 style and yes its 5 7/16 long compare to my original at 4 5/8 so they are not good for me . thanks everybody for your answers .