4spd is whats in it now. 2-4th are very close to what is in it. I currently use pretty much only 2-4th unless on a really steep hill or towing. Going from a 4.9 to 1 first to a 6.5 and from a 1.9 low to a 2.6 will be very nice. ill go from around 38 to 1 crawl ratio to around 70. With the 35's and stock 4:10s its max comfortable cruising speed is about 65. Thats about as fast as you want to go in that thing anyway. It will do a little over 80 flat out but it is a little scary.