I think this is a Spicer. I'm pretty sure it is a 411:1 from a 56 or ? Long story. Are these rear ends desirable? I've read swapping a complete axle would be the simplest. What other rear ends would be an easy swap? If its a 8" or a 9" where do you measure? Can I still get new gears to go to a 370:1? Can't go much over 55MPH. I already have an OD manual tranny. What tire size do you recommend? Can't find a chart for that? I'm trying to keep the leaf spring pads, drum brakes and 5x5.5 bolt pattern the same. Thanks

 

1959/67 F100: If Limited Slip was ordered, Ford installed Spicer (Dana) 44's. 9" wasn't available with Limited Slip in F100's until 1968.

Rear axle ID tag is located under 2 of the bolts that retains the inspection cover to housing. It appears from the 2nd pic you posted, that the ID tag is present on the right (passenger) side.

AXLE code stamped on the 2nd line-far right of the Rating Plate.

No 8" was installed in F100's. 1962/80 misc Ford/Merc midsized Passenger Cars (Mustang/Cougar/Fairlane/Torino/Falcon/Comet/Granada/Monarch and etc) only.