You can shorten the rear end of almost any car by cutting two small sections out of the axle and welding it back together. This is often done on older performance cars to accommodate the extra width of large racing tires. Most older muscle cars had simple straight axles that can be cut with an torch, and welded back with an arc welder. The differential and drive line hook back up exactly as they were before.
Jack up the car, block the front wheels, and remove the rear wheels, springs and shocks. Remove the axle and place it across two metal work stands.
Measure the amount on both sides of the axle that you want to remove. The amount to be cut out needs to be equal and symmetrical on both sides of the axle. Place one metal stand on both sides of the portions on both sides that you wish to cut out.
Clamp the axle to all four work stands so that when you cut out a section, the hub remains aligned with the differential.
Cut out the sections on both sides of the differential with an acetylene torch. Use a grinder to smooth the rough edges on the axle where you cut it.
Slide the axle back together. Grind rough edges with a hand grinder if needed to get a good fit. Use a straightedge to verify that your axle is straight. When the ends fit back together, use the arc welder to weld the axle back together.
Reinstall the rear end under the car just as you removed it.
