Suburban disc conversion question

[SidsChopShop]

Hello, I'm fairly new to the 67-72 year trucks. We own a very nice completely original 41k mile 1969 Suburban with front and rear power drum brakes. The rears are the standard size 2" shoes, the fronts are the 2 3/4" look like heavy duty drums.

I am wanting to do a 6 lug disc conversion, but am unsure if the heavy duty brake/spindle/ball joint combo measures the same as the standard 2" truck size. For those who have done this conversion, am I able to just order a spindle, rotor and caliper kit and mount the new spindle on my existing ball joints? Or will I have to order a complete kit with new upper and lower control arms with the compatible ball joint size?

Any help is appreciated, pic of truck attached. Thanks in advance.