These Northstar engines were an early attempt at modern light- weight small V-8 engines...If I'm not incorrect, they are smooth little operators...The main problem with them used to be blown head gaskets, caused by faulty head bolts...The fix was costly...I'm not sure if this was ever addressed by re-design....There is no mention of this flaw in the article...It was fairly pervasive in early editions of this engine.
Actually, Not quite what the issue was. It was worse, if you ask me. The aluminum used for the block just kinda powdered apart, so the bolts pulled right out. Made repairs nigh onto impossible. Plus, GM backed the timing WAY off on these things, so they didn't produce much power and and the gas mileage bit on them. To top it off, they made them pretty well impossible to tune, so even the aftermarket couldn't get much power out of them.
Kinda sad, because the basic design was quite sound, they made great noises and were very smooth. And the 4T80 transmission worked well with it, except for the fact that it was a gear or two short.
They made changes in 2000 and 2004, which were supposed to solve the problems. Who knows.
And don't ask how I learned all these things....