Lower control arm needed?

No sway bars, drag car. In fact I just threw front and rear sway bars in the scrap bin....

Just to be clear, only the upper ball joint is the large one right?
I can use my old 71 LCA, correct?

Exactly. I don’t know why j par keeps talking about upper ball joint spacers since you asked about the lower control arm.

The lower ball joints have different bolt spacing on the earlier drum spindles, but you just buy a disk brake lower ball joint, no need to change the LCA at all.