Real deal or move along?

The link wouldn't open for me but here in the rust belt, if I found a CA-sourced 8-1/4 from an a-body I'd be all over it for 250 bucks. And don't assume it needs a complete rebuild but the brakes need to be Checked out.

I have a 225 64 Valiant with a 3-on-the-tree and the 3.23 7-1/4.

I don't know what your ultimate goal is for your car but personally I wouldn't be obsessed with 4 wheel discs. If you're road racing, maybe. If you're putting around with your slanty, no. Unless you're only doing it for status then that's up to you. (Chevy guys around here install gear drives just for the sound)

One thing to consider is the wheel change necessary for the BBP. More money but the wheel selection is MUCH better. If it was me I'd start sourcing parts to do the BBP 73-76 front disc brake conversion and drive the sucker.

Yeah, I'm not obsessed with 4-wheel disc. As you pointed out I'm not racing so rear drums will be plenty adequate and I'm not interested in doing any of this for the status. My motivations for this work is safety, reliability and serviceability, plus I enjoy tinkering. As for the fronts, I was going to buy the CPP kit (around $900) which includes later B and E body front hubs, a new upper control arm, discs and calipers and a new power booster with dual master cylinder. The CPP kit will make the front pattern the same 5x4.5 and as you said, the rim selection is worlds better.