I need to hear from all the people who have blown up 7.5 rear ends. I am wondering if mine will last. It has richmond gears, an Eaton Pro series posi, and one of those fancy brace covers with--eek--stock axles. The down side is the 500 horse from the motor and the 3500 stall. The upside is no trans break and future plans for a Currie 9 inch. So shake up your magic 8 ball and tell me---------How long! Also share a horror story so I can feel better when this thing blows!

 

i think youre crazy running that setup on those little axles. 7.5s have been known to break on slightly modified stock engines. 4th gens cant use slicks because the rearend will snap under the load. the first thing you should have done is upgraded to at least a 8.5 10 bolt. it wouldnt have costed much from a junkyard and the rebuild would make it much stronger, plus it would bolt right in. ive heard people say that even 8.5" 10 bolts arent that strong, but others disagree. landspeed records have been set using them with beefed up parts, and theyre fairly common at the dragstrip.

 

8.5 10 bolt will 'bolt right in"
chevy350, do you even own a third-gen? Or seen the rear suspension of a third-gen?

In my experience, the diff housing is weak and deflects under load and the ring and pinion is small (regardless if it's richmond or not) and will be the first to break. The axles are weak, but the small ring gear is usually the first to go. How long it lasts, depends on how well you hook up. Could be your next pass, could be 50 away.

 

yeah no way an 8.5 10-bolt will blot in,

so far in my time ive killed 2- 10-bolt 7.5`s, both times the pinion gears teeth broke off as well as the ring gears teeth, (most recent one was 4 pinion teeth and 16 ring gear teeth) now of course these were factory rears with factory gears etc., with around 120k on them , ive also blown up a 120k 9-bolt as well, (one of the teeth broke off the pinion). This time around I opted to replace everything with new parts and see how long it lasts, I bought new 3.73 U.S. Gears, a complete install/bearing Kit, an SLP Zexel Posi Unit and 28 Spline axles, and a Summit aluminum support Girdle/Cover with the preload studs for the main caps. i also had my machinist weld the axle tubes all the way around. I am very hopeful that this rear will last me plenty of time, atleast until my supercharged stealthram 350 goes in.

i know there are plent of guys with 4thgens running 12`s on these rear ends, and there are some thirdgens doing it as well, how long it will last is questionable, and more related to engine and drivetrain combo and lets not forget driving style.

oh and heres a pic of what i found when i yanked the cover off my 10-bolt 3.23 posi last weekend. ill get some pics of how destroyed the gears are when i get them from the shop thats doin the install.

Matt