Usable power for the street?
What do you consider good steerable power?
Is that getting to be overkill for a street car?
Everyone will have a different opinion on this, but it really amounts to what YOU will be happy with.
Talk to some local guys, club members, friends; see if you can go for a ridealong in their cars. Compare notes between them to come up with some basics that make YOU happy.
Remember, there's more to it than just horsepower- on the street torque is king, and is what is going to keep that silly grin on your face. To that end, a nice torquey cam and some rear gears around 3.55 will go a long way towards that end; a little looser of a torque convertor as well if you're running an automatic.
I’m not looking to race the car, but do want to be able to break the tires loose easily from time to time and launch hard.
Think of it this way, I had an old C10 pickup with a tired smogger 307 and 3 on the tree and 3.70 ish gears that could break the tires loose at will, and if I threw a few engine blocks in the back would hook so hard it would snap your head back. Not exactly a horsepower machine.
So get some real-world, seat of the pants exposure and see what you like- "more is better" isn't always necessary.
And since you asked, in an A body I enjoy about 1hp-1ft.lb./c.i. to start, and gears around 3.55 for smaller engines and 3.23s for bigger ones- nice street manners and still able to defend her honor when needed. Not a world beater, but not a wallet-eater and still fun.
JMO.
