My 2nd rebuild on my 4L65E just blew up after around 20k miles. My car launches hard and I like to play so, when I'm playing parts are getting stressed even if most miles were just easy commuting. Is there any companies you guys would trust to build a reliable 4L65e or should I just suck it up and do a 4L80e upgrade?

Also: anyone know if the GTO shift linkage I have in my car work with a 4L80e?

 

Yes the 4L60E Family of Transmissions can be built for 650 HP and more...

However going to a 4L80E is more cost effective, and overall stronger.