Is your car a stick or automatic? I know these guys at the track I run at, who ran a low 13 second 289 with 351 heads with 4:10 gears, Mickey Thompson Slicks, C-4 manual valve body transmission, 3500 stall torque convertor, 28 spline 4 lug, stock traction lock posi. They never had any problems. I think they ran that set-up for 4 years. They now have a 351 with a spool in the rear, not sure if they upgraded to 31 spine, but it's still 4 lug, so maybe they have not gone to 31 spline. If you have a stick car, that is harder on the rear. I am sure everyone knows that. But an automatic launch is not as hard, depending on the stall on the torque convertor. So I would say if you are running an auto trans
, you are good for now. But consider upgrading the axles and posi at some point if you want to race alot. And what rear gear ratio do you have? The lower the number, the harder it is going to be on the car. For example, when I had my almost stock motor, T-5 transmission, 3:73's and Nitto drag radials and I had 31 spline axles, and a heavy duty eaton posi, launched at 4000- 4500rpms, all was fine. When I went to a Ford racing GT-40 crate motor, a new Tremec T-5z, which has a different 1st gear ratio, 2:95. The T-5 world class that I use to have had a 3:30, which worked great with the 3:73's. But with the new T-5z and lower first gear ratio, and hoosier quick time pro's , which are pretty much dot bias slicks, the car would bog and hook hard on the launch, which lead to in 2 years the clutches in my eaton posi being dust. Went to 4:30's and a Detroit locker.
It depends on what you have and how aggressive your launch's are, and how often you are going to run it. And yes! Get a drive shaft loop!