What gear ratio? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

baseball4lf8 · 01-27-2002, 14:30

I have a 67 and i want some low end gears for my 9" rear end. I want to be able to go faster off the line but still be able to go 70 on the interstate. I was thinking a 3.7 ratio but i have no idea. I will drag race the car at the local track for fun on weekends but its still going to be a daily driver so would this be a good choice? I was also looking at getting posi traction too. I wanted to put the gears in first and save to get the posi later so can i put the low gear into the posi when i get it or not? My car doesnt spin the tires which bothers me and i suspected it was the gears. I have a 3 speed automatic which doesnt help but i want it to jump off the line as fast as possible. What ratio do you recomend for what i want? What is the stock ratio? The lower the number the faster it will go off the line right? Thanks for the help!

Gearhead99 · 01-27-2002, 17:31

I think that 3.70 is OK. But, you will probably find that the 3.50 are more of a good for everything ratio. I run 3.50 in my 68 FB and they work good. I can still cruise on the highway. But, you'll be turning 3000 rpm at 65 mph. Up or down alittle depending on tire size.

Last year I removed the C-4 and installed an AOD transmission. What a difference on the cruise rpm now. I did change the convertor to an Art Carr convertor without lock-up. The O/D pulls the rpm down about 1000 rpm at cruise.

01-28-2002, 10:02

I got 3.89s in my car and they are just too much. Without slicks on the car you cannot take advantage of it! I can turn my car sideways at the track with my open 9" if I hit 2nd gear with full power. The 389s with 245/60/14s are 4000 rpms at 80 mph. I am going to go back in and put 3.55s in. It just is too much advantage for street tires.