Alright getting ready to put together a awesome racing tranny. Right now I just want to put in a FD. Which one is going to be better for top end. 4.7 or 4.9? I read somewhere that someone used a 4.9 and topped out @ like 120 mph? I would like some nice acceleration but would like to top out a little above 120. Bah I don't know. How often you gona hit 120 right? Anyway so which one is gona be the best for the 1320 and the Road Course?