Thanks for the replies all! Once I started looking into the LT1 and 8 speed, I really was struggling with whether or not 640hp would be too much. On the one hand, I likely don't NEED it for this build, but on the other, that power increase per $ is really hard to beat. It's been soooo long since I have driven this thing, I don't remember what 400hp was like. And I was in my teens/early 20s then as well, so my right-foot maturity is likely better now than it was then
.
I'd definitely want to go with numerically lower gears and wider tires though, as with the gear spread and power 3.73 gears would likely be way overkill.