I've blown up two 742 and one 489 case. BUT.... It's only the sure grips and one bearing cap that have fragged. Go with a Detroit locker and the damn things are damn close to bullet proof. I also attribute the attrition rate to my "burnouts that can be seen from space" driving style. With my experience I wouldn't even consider a 741 case. Go as beefy as possible and avoid the stock "posi". ~John -----Original Message----- From: Joe [mailto:jgray_55@xxxxxxxxx] Sent: Tuesday, November 02, 2004 1:24 AM To: AMClist; BadAssGremlins Subject: Mopar 8 3/4 rear strengths? Anbody familiar with the Mopar 8 3/4 rearends? I'm going to instal a road runner housing assy in our 74 AMX behind the freshly built up 401(9:5/1 compression/comp 280H..ported heads... 1 7/8 headers,..etc..Question..there are three diffrental 8 3/4 differental casings..# 741,742,489. I know the 741 is the smallest diameter pinion shaft and is the weakest..BUT..HOW weak? Anyone used one? I've located several 741's and a couple of 742's that i can swap some parts to get.Thanks for any help, Joe(still trying to finish this car for my wife after gettin laid off....SUCKSSSS) __________________________________ Do you Yahoo!? Check out the new Yahoo! Front Page. www.yahoo.com