Classic Industries OER front conversion question

72bluNblu said

I don't think many of the OE style are selling anymore. Even with the offset UCA bushings the positive caster is pretty limited with the OE style UCA's. Unless you're running bias ply's running the tubular UCA's and the additional caster they have built in is a pretty good idea.

Click to expand...

I am perplexed, my 1972 Duster 340 has manual drum brakes and I want to convert to 11.75 discs following the (disco-tech) system.
I bought the QA1 tubular upper control arms and adjustable strut rods.
I'm keeping the lower control arms. They are refurbed / boxed with Delrin bushings.
Do I need to back up and get big ball joint uppers? Can I continue with the QA1 tubular uppers that I have?