[hotford]

Anything over 500 rwhp and it's on borrowed time, I have two cars that run 4R70w, when my Marauder had a trilogy and was making 440 rwhp it was fine, once I ramped up the power I went and had it built with hardened input and output shafts and with extra clutches in the drums also a good shift kit, today it holds 680 rwhp plus with the stock torque with no issues.

My other in now in the Mach build I have going on but came out of my GT car that made over 700 rwhp and it too is built the same as the marauder one with the exception of a Circle D convertor.

Both cars I might add have external coolers on them.

The tuner play's a big part in the trans life cycle, having someone that knows that trans and can tune it will make a huge difference.