when to rebuild and engine
 

I'v got a 94 V6 Camaro with about 142,000+ miles. I change the oil regularly, service the transmision at the begining of every year, flush out the cooling system every 6 to 8 months(had a really bad episode with my cooling system so don't ask why I'm so presistant about keeping it clean), and generaly take very good care of it. But I do drive it on the hard side and wondering when I should rebuild it before something bad happens to it like blowing a piston ring or an oil pump going out and having to buy a whole new engine.

And one other question when should I get my transmision rebuilt

Thanks