Was thinking about switching my 3.73 gears to 3.89 or maybe even 4.10. Just wanted to see who is running either of these, and if they like them. What kinda rpms are you running at 70mph, the car is not a daily driver but i still want to run on the freeway once and awhile. The car is a manual 1998 gt w/pi parts and all the bolt ons,and 125 shot of nitrous. Thanks in advance!
I've never heard of 3.89s so I'm just going to assume you mean 3.90. The 3.90 is not a Ford gear thus you cannot correct the speedo for it with different gears. Its all personal preference, but since you don't drive it daily and you're debating between the two I'd go with 4.10.
making the switch from 3:73's to 3:90's will hardly even be noticable...going to 4:10's would be the way to go, not really THAT bad on the highway. You'll see slightly higher RPMs than the 3:73's but you wont see a night and day difference. But remember, with the laughing gas, traction may become a problem if you go with more gear (if it's not already)...you should get a good pair of drag radials.
yeah, that's another thing with the go-go juice and 4:10's. IMO, since you already have 3:73's, I would stay with those. Spend the money elsewhere.