disk brakes on Model A spindle

I want to put disk brakes on my '30 Model A. Axle is original. Speedway brake kits say '37-48 model spindles. Will the '30 model spindles work ok with the rotors or do I need to change them to later spindles? anybody?

 

The Caliper Bracket Has a different/bigger bolt pattern than the Model A. Get 39-48 Spindles.

 

I Through they made a kit to fit that 30 good luck.

 

Thanks. Appreciate the info.