If you to GM to buy a crate motor, the LS7 is a bunch more money than the LSA. If I recall correctly, just buying crate motors the LS7 is at least $5,000 more than the LS9.
And I know every hot rodder on this sight can get more HP out of an LS7, to meet ALL of GMs requirements for durability, the LS7 is really at the ragged edge. Any more and you'd have an engine that would be breaking.
And the LS7 already has the highest tech hardware in it. I mean it has Titanium connecting rods
So always keep in mind, what the hot rodders and tuners can do is different that what GM can do simply because GM warranties it for 5 years and 100,000 miles. It needs to make great HP, but also be strong and durable.
Don't get me wrong either, I love the LS7 and I love the power it makes as a NA engine. But unless GM finds away around "hand making every one", the LS7 the costs are very prohibitive. The LSA is made at higher production volumes in a more "normal" plant.
It is truly a great idea, but when you say GM should have used it, you can't also create more HP. It is a 505 HP answer and from what I'm told there isn't much more blood to wring out of the stone................and be durable.