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Almost 8 years later and there's no reason to change one word. At VIR road coarse the 96 Limo, sans the German Shepherd/Wolf Hybrids, could match the lap time of a C5 Corvette. The LT-1 Stroker has something to do with that in addition to the suspension/chassis work and yes I still have that car. Even in Zurich it's a rare one.
Scott, a little off topic but I was wondering what you thought about this.

I boxed my chassis, welded in some 1 3/4" .090 wall tubing between the rear rails as a 'RMS brace', bolted in DMR bars etc...

one thing that still shocks me is how much the frame still flexes up and down when jacking the front of the car up. when the suspension is unloaded and the chassis is on 4 jack stands, you can visibly see how much flex there is when jacking up the front before the rest of the chassis actually moves. Basically what I'm saying is the front engine cradle sags quite a bit when the chassis is suspended by jack stands.

This makes me wonder what, if any effect this is having on handling when the car is on the road. Not an easy fix, the only way I could think of resolving that issue is tying the front frame rail horns together witn the rest of the chassis via roll cage.

My gut tells me that this problem would only be apparent when the car is sitting on jack stands the way it is now because the jack stands are creating a fulcrum point just behind the engine cradle but I keep wondering if this is something that would affect handling when the car is on the road. What do you think?
 

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Back in the very early nineties Specialty Vehicles International had customers in the middle east who payed over $100, 000 for brand new Caprice SS's modified with superchargers, T-56 conversions and Brembo Big Brake kits. Brand new Impala SS by 94 for ~$21K, when OEM. Buy 11, get one free. All of the mods in the above posts got done as well. An obvious question was just how much improvement would a Progressive Automotive radically rigid frame make? $6000 later we got the answer; not so much. That one car got experimented with a lot, in fact, my daughter Lisbeth still drives it and it's solid as a rock, but it doesn't really justify the $ spent on the frame.
The Law of Diminishing Returns.
Steel produces a spring rate, a fourth order equation based on the structure.The more you eliminate the body roll, the more you flex the frame. With a soft sprung car with little roll resistance, turn the wheel and the tires slip angle energy goes into body roll. You can see where the frame can bend when you jack it up. You can weld on so much steel the weight gain will be silly and you'll still have spring rate in the frame. (That's what Progressive proved to us) So...
Here's the good news. The frame doesn't have to be Infinitely Rigid or even close for you to have a neutral, excellent performing car that even rides nicely, if in a controlled, firm way. Like a Bentley Arnage very limited edition R.
Fun fact. For the 500 HP with 600 pounds of torque, limited edition R model, Bentley bought GM 4L60E's, replaced the sun shields and clutch packs and a few 20 cent pieces of plastic and they were the most reliable transmissions Bentley ever put in a production car. When people managed to break them, Bentley sold them over their parts counter for almost $30, 000. A mark up to put even SVI to shame.
 
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