Signal7

For a 4th gen with an auto, which setup would stress the rear end worse? A full bolt-on stock LS1 engine car with a Yank 4000 or a car with a turbo making 450-500 horsepower? With the turbo car having a 3400 or so turbo converter.

RPM WS6

iTrader: (3)

Power alone isn't as much of a factor as things like wheel hop and launch shock (traction). Here's an interesting thread on durability of the 7.5" with an auto (as opposed to a manual). You'll see that the rear can take quite a bit with an auto as long as things like wheel hop are not present:

Best 60 Foot on Stock 7.5"?

Y2K_Frenzy

I imagine the turbo car would spank the dog sht out of the bolt-on car even if the turbo car had the stock stall. Turbo that thing. It’ll be “quick” and “fast” vs just “quick” with the stall. Drag car or street car?

mk3cn4

iTrader: (3)

Here's my take on it. When you are considering the strength of a stock diff, it's all about the "shock" on the driveline. I think every broken diff at the track I've seen was a stick shift throwing an instant SHOCK to the rear. And it's the launch torque you need to consider, not the top end horsepower number.

My belief is that an auto, especially a stalled auto, doesn't have the shock instantly, and therefore whatever shock there is gets spread over more teeth in the diff over time. So same power spread out over more of a surface basically. Even when revved to the TC wall, there is still a little slip/buffer action happening instead of an instant dump.

And as mentioned, wheel hop and other things like that count as shock as the wheel spins free and slams back to road speed.

I think in your example it'd not be much different between those two.