I had 5.14 gears in an '68 Camaro with a small block 327 back in the day. 2 speed powerglide w/ nitrous. It was a 8 sec. street car back in highschool. Obviously a little different gear then your post suggest, but nothing I'd even consider putting on the freeway. I think 4.30's would put you close to being in that same category. Unless your planning on putting the thing on a trailer to get it to the track, it's too much.
i have a gt/cs with exhaust, ive thrown around the idea of 410s or 373s, not sure which one i should get yet..hows the gas with 410s?