Hello, up for sale is a rare high performance 55-64 Impala, Corvette and Trifive Chevy drop out 3rd member that was upgraded with heavy duty 30 spline Dana 44 spider gears. This desirable hotrodders upgrade cures the weak 17 spline standard rear issues for higher horsepower applications. The thin P case C1 corvette style posi case is set up with the factory correct Armasteel 3 series posi and factory GM 3.36 ring and pinion. The posi chunk was set up for a 55 Chevy in the 70s, removed and dry stored for decades. The case, posi unit and gears all look good with no visible issues. This would be a durable upgrade to your higher horsepower Solid Axle Vette, Trifive Chevy, Impala SS 409 or BBC Hotrod. Please call or text for more info at 3o2 Five84 seven88five. I don't check email. Thanks for looking!