Caltracs vs Slide A link Vs SS springs
You can run cal-tracs with a set of stock worn out a-body leaf springs. We had a 10 inch tire car running high 9's on such a set up. Are the cal-trac split mono's better? Probably.
You are going to need a good set of shocks anyways so that's a wash in the expense column.
Plus, with cal-tracs, you won't end up with a stinkbug looking, bad riding, stiff as crap rear suspension car. If you need to raise the rear to fit a tire, get different wheels/tires to get them in the well would be my suggestion.
I'm doing a mini-tub and relocation kit on my 71 Duster now... it's getting a set of Cal-Trac style bars with the worn out A body springs.