Help with brakes on 64 Valiant please

(I posted this in the early a body forum before I realized there was a dedicated brake forum-sorry mods)

I will be converting my front drum brakes to Wilwoods front disc brake conversion for my 64 Valiant. I was all set to purchase the 9in kit. I was told it had the original drums.

Did 64's only come in 9 inch drums?

However, when I measured the studs I discovered I have large bolt pattern.



I wasn't sure how the car could have LBP on 9 in drums so when I removed the wheel I saw this....





Looks like they re-drilled the brake drums and put the long studs. Not sure
how common that is to do. I have seen the rear axles being drilled through but not fronts. Anyone else seen this?

So now I am not sure if I have 9 or 10 inch drums and spindles. Is there way to easily tell what size these are? I need to order the brake kit this week and don't want to order the wrong kit.

I measured the back of the drum at 10 inches.



Is the only way to tell for sure to take the drum off and measure the inside diameter to know if it is 9" or 10"?

Thanks in advance for your help.

( wheels are 15 in Weld Racing)

pic of car is this matters...