A weak rear end!?

[FormulaRX7]

I was at a performance shop earlier this week and i started talking to this guy about my bird and such and he told me that GM put the weakest rear end into the firebird and i was shocked at this. Is it true? and if so what can i do to beef up the strength of the rear, last thing i want to do is damage the car.

[Mr. Luos]

Sticky tires at the track will kill it.

If you are stock, nothing to worry about unless you bolt on slicks to race.

[Matt365]

drop some stuff to do to beef up the rear end, i am also interested with this.

[LowETz]

Use a girdle w/the pinion cap brace studs. Helps to stiffen the housing by eliminating any deflection and the cap studs help keep the pinion from "walking".

Other than that.... not too much you can do other than stronger axles but they aren't usually what fails. Nine times out of ten the ring gear scatters taking the pinion and sometimes carrier w/it.

If you're going to launch the car hard with the ten bolt/7.5" rear, I wouldn't use much more than a drag radial, and try to pre-load the rear at the line before launch to take out the slack between the ring/pinion gears. Also when launching, don't just drop the clutch, try to feather it(all be it quickly)out of the hole..... seems to help 'em last a bit longer.

One other thing.... the stock suspension components are notorious for wheel hop which will suck the life out of the stock rear at a faster rate. Invest in some adjustable LCA's, and LCA relocation brackets if you're getting any significant wheel hop.

[tuske427]

Supposedly, the rear in our beloved F-bodies originated in the Vega, and has evolved since. it was a 7.5" in the third gen and 7.625 in the 4th. Not much of an improvement.

After one time at Irwindale raceway with my '95 T/A the rear was making noises. I replaced the carrier with an auburn posi and replaced the stock 3:42 with richmond 3:73 and used a studded differential cover. (also replaced all the bearings and seals, too) that solved my problems, but my engine was only pushing around 350 horses.

Mods like this will be fine for a mildly modified LS1 or LT1. If you're under 500 horses and you're not constantly drag racing you shouldn't need to replace the axle/ housing. (If you do, check out companies like Moser engineering and they can set you up with a 12 bolt that will bolt right in)

The previously mentioned pre-loading is a good idea and will lessen the "shock" on the rear.

I hope this is helpful.

[Mr. Luos]

Originally Posted by tuske427

Mods like this will be fine for a mildly modified LS1 or LT1. If you're under 500 horses and you're not constantly drag racing you shouldn't need to replace the axle/ housing. (If you do, check out companies like Moser engineering and they can set you up with a 12 bolt that will bolt right in)

I have heard of guys popping their rearends with a stock motor.
DR's would be the only thing.