Another 390 gear question
I've read a bunch and decided that 3.90s would suit me best, I have a long commute that I drive about once a week w/ my TA, I won't be going to the track (maybe once or twice). I then read that 3.90s can't be used on a stock rear, is this correct? What would I have to do to go w/ 3.90s as opposed to 4.10s? While I'm firing away w/ questions, how much MPG loss would I incur (stock to 390/410s?) w/ a pretty much stock car?
Thanks
Thanks


