Subframe connectors for a driver/cruiser, necessary to weld to floor?

MRGTX said
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The thing that seems to be missing here is the debate over torque boxes. I have no data to back this up but the Torque boxes may actually be more important since this is what Mopar chose for factory high performance equipped cars.
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72bluNblu said
Torque boxes might still be something for you to consider. They do stiffen up the chassis, and they can be installed with a fairly small amount of welding. For a fairly small addition, stiffening the corners the way they do does make a difference. I don't think they take the place of subframe connectors, but they are what the factory used for convertibles and higher horsepower cars.

There’s an echo in here. :D

Based on the historical application of these two measures, I think there is a strong case for the OP to use this option. His car sounds like it has been upgraded to at least the level of cars that would have come with this equipment and while it’s not being raced, it’s not being driven like a fragile Model T nor is it being put-putted around to car shows like a *gasp* priceless Hemicuda either.

I guess the problem is that it’s very hard to have real data on how much these things help and therefore very hard to compare one chassis flex countermeasure over another. Nobody is sacrificing their own car to chassis rigidity testing and even if they did, these are all half-century old, used and often abused platforms making control data nigh impossible to come by.

Anecdotally, torque boxes seem to have made a huge difference in preventing chassis twisting/long term damage when big power and slicks were added to the formula…so even without data, I’m pretty confident that they do something helpful.