Front suspension options

I'm not trying to discourage you, I'm just trying to realistic. If you want to do all of that custom fabrication, I would actually love to see it. Seriously, if it worked better I'd be willing to look into it myself. All I'm trying to do is point out that the amount of work necessary to make a Crown Vic suspension fit and work properly on an A-body will far exceed what I think you've planned for. If it was an easy, low cost affair people would already be doing it. The welder alone will charge you over $500, and that's if he's in a BIG hurry and you did all of the jig work. If the welder has to, or insists on, jigging the cradle (as he should if he's worth his salt) I bet the welding costs will easily be over $1k. Welders are not cheap, TIG welding is not fast, and welding cast aluminum is not something you want to trust to just anyone.

As for the stock suspension, it is great. The fastest, track proven handling mopars around right now all run torsion bars. The Hotchkis Taxi, a freaking 4 door Satellite, laps faster than the 2012 3 series BMW's on Tire Rack's test course when both are driven by Tire Rack's test driver. So, how is the stock system inadequate?

Why are there so many coilover conversions being made? There's a few reasons. First, until the last 3 or 4 years, there has been very little in the way of aftermarket support for upgrading the torsion bar suspension. That's not the case anymore, with Hotchkis and QA1 making all kinds of stuff, in addition to the parts that were available before from places like Firm Feel, not to mention all the newer start ups making great stuff like Bergman Auto Craft. Second, most people don't understand how a torsion bar suspension works. It's really that simple, people don't get it, so they replace it. Torsion bars are just springs, so are coilovers, there's no magic. Third, folks assume that it's easier to just bolt on a complete replacement than fix the stock system, which usually is abysmal because of 40+ years of wear and being set up for bias plys to begin with. They assume if it's that bad it's not worth saving, when in truth it just needs a few relatively minor upgrades. Fourth, there's enough late model engine conversions and such being done now that in some cases the torsion bars really are a problem in the real estate department, and if you can buy a new crossmember already set up for a GenIII hemi it starts to make sense. And finally, there's enough people that own these cars who have no mechanical inclination at all, but posses large wallets, that just go out and buy the shiniest all in one conversion that money can buy because it "must be better".

As for the chassis, you're not considering how the stock suspension really carries and loads the chassis. All of the vertical suspension motion is translated into rotational force by the lower control arm, which carries all of the load. Yes, the suspension moves up and down, but the force is not carried vertically. It's translated into rotational force, and that's what the crossmember and K frame "see". The coilover suspension and crown vic suspension translates the suspension force into vertical force. It puts the load on the LCA and the upper coilover mount. Even if those are included in the package, like with the Crown vic and a the better coilover conversions, that still stresses the frame rails differently than the rotational force applied by the torsion bars. Even with the torsion bars, the front frame rails flap about and should be reinforced. With the crown vic or coilover set ups, it MUST be reinforced.

As for actual math, good luck. To actually produce something that would mean something you'd need a full structural analysis of the chassis, and then do it again for each system including your one off Crown Vic set up. I've done them before, but the software and computing power necessary would require someone that's actually in the engineering industry.