I was just reading the tech article about swapping a 4th. generation rear into the 3rd. gen cars.

I think this is a swap that I would like to tackle, but the article didn't mention what year of 4th. gen cars carried the strongest rear end. How much abuse can a 4th. gen rear handle compared to a third generation?

Will the lower control arm relocation brackets for a third gen weld up to the 4th gen rear or will I have to buy the brackets for the 4th. generation?

 

The LS1 rears would be the best. They're not a whole lot stronger than the LT1s, but the LS1s come with the torsen posi. In terms of horsepower, I wouldn't go much more than 300, especially if you have sticky tires. Yup LCA relocation brackets will bolt/weld up just like they would on a third gen rear.

 

If the 4th gen rear was rebuilt with "GOOD QUALITY" parts, would it be able to handle 500-600 hp? Or should I continue saving for the Moser rear Spohn sells?

 

Auto's are fine with most stock rear ends.
the manual tranny's destroy the rears.
My old 96 Trans Am LT1 6 speed with bolt ons went through a total of 14 rear ends over 5 years.

My 88 Formula has already popped 3 rears and I don't have that much power.

 

Not even close. The 10-bolt with an aftermarket posi unit and stronger axles and gears is good for about 400 HP. Anything close to or more than that, and you're asking for trouble.

I think there is a tech article on this site about "Beefing up the 10-bolt" so take a look at that.

 

This is an interesting point since Firehawks and SS camaros came with 330-350 HP.

So an unmodified rear end would grenade on a stock firehawk or SS camaro?

 

If you have a 6 speed or an auto with sticky tires. Once the tires hook, pray the rear doesn't go ka-boom.

I see no real point in beefing up a 10 bolt, that money is much better saved to put towards a 12bolt or 9".

I had a built 10 bolt and I broke it with my formula. that was the last thing I would have expected to break on my car.
Eaton Posi, Moser Axles, Motive 4.10 Gears, Solid Pinion Spacer, all new races and bearings, and a TA Cover with Stud Girdle, about $1150 in parts.

Right now I am cruising around with a stock 10bolt from an 01 SS 6 speed..

 

I guess that answered my question. $1150.00 in parts & I'm going to guess $500 to a grand to buy a used 10 bolt depending on the condition of the rear end.

Thats getting close to the price of that Moser 12 bolt I was looking at. I think I may roll up some more pennies & give Spohn a call.

 

Yes, I have read many stories of stock 4th gens and even thirdgens breaking 10-bolt rear ends. And I have read stories of 11 second 4th gens with stock rear ends. Its all a matter of luck.