my car had a 2.8 mpfi auto now its pushing 350 sb th400 yadda yadda i give her its first smoke show yesturday BOOM lights it up huge! no posi one wheel fire tire it was tight for what it was then today lay a patch BOTH tires spinnin em.. i get the girl behind to tell me whats gowin on she says both tires spin equally i dont get it at all someone? here help? where can i run my VIN to find out what rearend and ratio im running im confused??

 

Pop the cover off & look for 4 small spider gears. If so you have an open rear, a solid ring gear carrier with a clutch pack in it is a posi. Looking for factory codes on a modified car that old is probably useless since it probably has been changed. The two wheel spin test isn't always accurate as a posi could be slipping & an open rear sometimes will spin both.