You're already making assumptions. You have no idea if an A-body is stiffer than a B-body. Yes, they're both unibodies. But let me ask you, which one has the longer span between the frame rails?
On my '72 Challenger, the length between the frame rails is almost identical to the length on my Duster. And you know what that means? It means that the span on my '71 Dart is longer. That's right, my '71 Dart has longer frame connectors than my '72 Challenger. And even longer frame connectors than a 70-74 Barracuda, because their subframe connectors are even shorter than the Challengers.
And what's the width? Well, the B and E body cars have wider frame rails. Which completely changes the math. The frame rails don't have the same cross sectional areas either. Which changes the math again. You can't say that a B or E body has more flex just because the car was bigger. Roof height and length make a difference too. There are too many variables to make basic assumptions like that.
I'd put subframe connectors in ANY Mopar I intended to drive.
You're right, this is all way over your head.
Even in your own comparison, you don't have nearly enough facts to have an informed opinion. You don't even know that the big three didn't have concerns about frame flex. I'm sure they did. But more than likely, they decided their product would last long enough that they wouldn't get sued to the point of not turning a profit. They figured the truck would last long enough to be replaced by the next one, not necessarily that they made the best product.
