I have another question to ask you guys in reference of my 1957 Chevy 1300 truck. The rear end is a 10 bolt but I do not know if it is a positive traction or not. I have jacked up the rear end of the truck and spun the tires while the transmission is in park. The tires spin in opposite directions when I do this. I have also spun the tires with the transmission in drive. The opposite tire does not spin at all when I do this. Any suggestions are appreciated. Also where can I locate the numbers for the rear end. I have located some but I doubt that these numbers are the numbers needed to determine the type of rear end. The numbers read as follows 2018188.