That rear end held my car no problem with 470 rwhp and 373 ft/lbs. And handled multiple low 10 second passes on pats car. I think a semi stock ls1 will be fine.
i also got an ls1 motor being sold soon…
Some people are stuck thinking that if its a 4cyl it won’t make torque.
Good luck with your swap. I can think of a couple guys off the top of my head that have some experience with that swap!