Okay here is what I want to know. How much realistically can I modify my vette, and still be able to have it as a daily driver with decent (something more than 10 mpg) gas mileage?

I want 400 hp at least, and as I am reading various topics here I will also need to upgrade my transmission (its an auto) and rear end...

So someone please enlighten me....

 

Very realistic, slap on a supercharger and you're there. Oh is that RWhp or crank hp, for rw you might need heads and a cam aswell. Still very driveable on the street and decent gasmileage, 20+ highway?

 

The things that make something what someone would call "unstreetable" are more than just mileage, and will vary from person to person here. You can get somewhat decent mileage with a 350 even with strong combinations, you just might not get anything much more than 10-12 in town.

With a 93, you can get the 400hp (crank) or just about that much, with ported heads, RR, LT4 Hotcam, and exhaust. Although the hotcam may not be quite ideal for an automatic, depending on driving preferences. It makes its power at higher rpms, and you might want something more low/midrange. I would figure that this should still make good mileage, with tuning.

You wont need the rear modified to handle the power, unless you drag race. Then it becomes necessary to change to Dana 44, otherwise you will eventually blow that rear. Maybe not the first day, maybe it'll last 1000 passes, but it will go sooner or later, especially on slicks=boom.

Tranny will definitely need a cooler installed, thats all it requires, but for precaution you would be best off having one professionally rebuilt with upgraded soft and hard parts if you want it to last 20K+ (some round number, i'm just guessin). Not to say it WILL blow after the engine stuff is done, but theres a damn good chance.