I have a buddy with a 2000 Z71 with a 5.3L. He had the original engine replaced a few years back and around 160k miles. I still believe it just needed valve seals but he wanted a new engine. It was just smoking at startup.

Anyway he offered the old engine to me for free I just have to go pick it up. It's been sitting outside for a couple years so I don't know if it's usable but I guess it's worth checking out.

My main question is, is it worth freshening it up and building an iron 5.7L to swap in place of my 4.8L? I'd cam it for sure. I know that more cubes is always better but I just wonder if it would be worth doing or just find a 6.0. It's hard to beat free but I guess the cost of rebuilding it is a factor too. Either that or I could play with my current motor.

 

A used running 6.0 would be cheaper than a rebuild. Especially over boring to 5.7.

A rebuild, Assuming the major parts aar reuseable does lend you to learn about these power plants as well as taking pride in your own work. plus you can do it a little at a time as you can afford.