Backhalving?

Because as any good racer will tell you (and it's also in the original Direct Connection race manuals) that your car, and engine are only as good as the chassis they are put in. The chassis is what takes the power and plants it to the ground. You can take a lower horsepower motor and go faster with a good chassis then you can with a high horsepower motor and poor or marginal chassis.

Even the Pro Stock guys will tell you, you can buy the high horsepower motors but without the chassis and the proper set up you aren't going to be competitive.

So why not build it once, then you won't have to redo the interior, paint the quarter panels again because you had to stretch the wheel wells, redo the roll cage, change your fuel and electrical systems around, etc., etc. It's not just as simple as removing those parts and then back halfing the car. You will spend way more than just the cost of those CalTracs.