Aside from the caster/camber interdependence, the Mopar design was and still is very good.
I agree, and to a large degree, no single area is less robust then it needs to be relative to all the other components, which to me means a balanced design.
Welding up the K frame resolves a few other issues than simple engine bay flex. The K is the primary loaded structure in the front end. With supporting the engine, steering box, and the front torsion bar/control arm anchors as well as being spot welded together, welding it up provides a big boost in rigidity to a number of components in addition to the front section of the car.
I agree also, and the fact that it directly support the largest/highest density single mass on the vehicle.
Because the upper control arm mounts and shock mounts are not radically loaded in a mopar, the shock tower braces is less about providing loading support than it is of increasing the rigidity of the simply cube structure that is the engine bay. By turning it into multiple smaller triangles, you can reduce the flex. Percentage of improvement by doing this, I can't quote a number.
Not sure how we define "radically" here. but with my back of the napkin thinking, since most all wheel forces transmit thru the front spindle, and the spindle being vertically approx 1/3 above the lower BJ, and the upper BJ approx 2/3 above the spindle, I think it would safe to assume the loads proportioned between the upper and lower as nearly the same ratio. And IMO, the K frame has much greater designed in robustness then the UCA mounting pivot points, beyond the above mentioned ratio, and the UCA apivot area would be an area next focused on, after the low hanging fruit upgrade of welding up the K member.
Because of the lack of loading in the upper parts of the engine bay, mounting a brace to the firewall can be effective in a mopar, but there is a question in my mind about putting structure that mounts in a large flat plane of sheet that doesn't make me think it is the most effective way to do it.
I always assumed two things on a well designed/installed
Monte Carlo brace on a Mopar, if achievable, both triangle braces from ea fender area would meet at a center node, and that node would also be on a seamed/flanged 90 degree joint of two metal OEM panels.
I read a white paper on nascar design sometime ago. In it they stated that the most heavily loaded area is the firewall/a pillar area. While we aren't running out cars are near 200 mph speeds on superspeedways, it does seem logical to say that improvements in this area on a performance street car can yield gains as well, especially since we lack all the triangulation structure they have in this spot.
I wonder in the above if, "Heavily loaded" really means "loaded", or "highly stressed"?
