There are several thnigs that come into play on how long the 8 3/4 will last,if it is a foot brake that is a one in the plus column, if a trans brake or stick shift car go straight to a Dana 60 If the car is over 3300 lbs with driver and is going to be able to run in the low 1.40 or 1.3 in the 60 ft. look hard at a Dana 60 If it is raced on bad tracks that the cars spins and then hooks look at using a Dana 60. If you decide to use the 8 3/4 back brace the housing, buy and install a steel cap for the drivers side of the third member, use the highest pinion tooth count you can live with, IE use a 4.30 instead of a 4.89 ratio. Buy a good set of race 35 spline axles and a 35 spline spool, if it is a street car and you absolutely must use a posi you should buy a good set of axles If you use a "489" case throw the crush sleeve away and buy a pinion spacer to use to set the pinion depth and the pinion bearing preload I used a 8 3/4 in my Duster with ladder bars without a back brace, bad decision on my part I ended up bending the housing so bad it broke the welds off of the ladder bar mounts During a run The decision is your freinds to make, I bought a junkyard Dana 60 out of Ford 3/4 ton truck and had it narrowed Look around, sometimes you can find a Dana 60 in a junkyard that they took in as a core that has a bad axle housing end that has the ring and pinion and sometimes a posi I use to buy them for less than a hundred dollars and sell them for $150.00 to the other brand racers that had broken thier indestrutrable 12 bolts and 9 inch rar ends