I'm thinking of going with 3.73 gears, i've recently put 17x11 ZR1 wheels on the back end of the car, running street tires... a new engine going in as well, with some head work and the hotcam... would all this be too much for the 10 bolt?

 

as long as you dont launch too hard, i think you might be ok for a while. If i were you, i would start putting money away on either a new rear end, or a rebuild, though.

trav

 

Definetely put money away for a 12bolt. Yeah, I installed last spring 3.73 in my stock rearend. And last fall with a hard launchwith my nitto drag radials in back and my awesome spec stage 3 clutch it grabbed and busted the driver's side axel and broke the spidergears on the posi. So I had to spend on a 12bolt moser rearend which I upgraded gears to 4.10. Best investment ever. My rearend can handle just about anything now.
The stock 10bolts are really weak!

 

A friend of mine is running a 10 bolt, stock axles, solid pinion spacer (extremely important!) TA cover(girdle) 4.10 gear on a 95 LT1 383. He has an automatic, with a 2800 stall and BF drag radials. No problems at all for allmost 2 years of racing. He runs 12.40's @ 111 mph. It's a 10.25 to 1, LT1 heads mild bowl blend, Manley race-flow valves 1.94/1.50, Comp springs, custom grind Comp 220/232 @ .050, .510 .535 lift, 114 LSA, 52 mm TB, 30# injectors, PCM for less, 1 5/8 shorties, dual cats etc...His cam was designed with N2O in mind, but he has not yet tried that. I would say that if you run an automatic, 2800 or less stall, no nitrous, you would be ok. Many shops will tell you that the solid pinion spacer is unecessary but it may be because they don't know how, or don't want to take the necessary time to set it up. It is sold by Raytech. There was an article a few years back in Chevy Hi Perf where they had a 98 LS1 6 speed manual running high 10's with 5,500 rpm launches on a 10 bolt with spacer and girdle. They lunched the thing and eventually put a Moser 12 bolt in it. I think I remember them saying the stock rear lasted about 30 runs of severe abuse before it blew.

 

does hard shifting in say a M6 cause similar stress to the rear end like a hard launch would but to a lesser degree?

 

I think it depends on how hard your clutch "hits". I have a spec stage 1 and it drives like a stock clutch. Now a stage3 will most likely seem more like a launch because it disengages so hard.