OK so Im trying to figure out why some people choose to go with different rear end gear ratios, I dont exactly understand what the pros and cons are when dealing with 3.25:1, 3.75:1, or the famous 4.10:1..could ya'll be kind enough to help me out here?..Im trying to figure out what ratio I should go with in the 9" Ford rear end Im planning to build up..Thanks

 

it all depends on what you are doing with the car. a numerically lower gear, 2:73 for instance will provide lower operation RPM, great for highway cruising and gas mileage. Numerically higher gear cause the engine to rev faster, thus more seat of the pants feel and acceleration, though they can limit your top end speed. Numerically higher gears are also used in drag racing to get the engine at the peak of its power-band as it crosses the finish line.

For a street performance car, 3:23 3:42 3:73 are good choices, anything higher, 4:10, 4:56 , ect are generally more for drag racing.
It all depends on the usage and powerband of the car.

 

Thanks 86TA
I have a stock 305 but I am going to build it up to about 300-350 hp...and I will use it as a daily driver so fuel efficiency is deffinitely a priority but I still want that aggressive acceleration..wut would be a suitable gear ratio

 

if yur car is a stick car i would go with about a 3.55 gear and if its and auto then id go with a 3.23 or a 3.25, i got about 23mpg in my 87 305tpi with and 700r4 on 3.23 gears

 

I have a 3.23 4th gen rear and I get good gas mileage.I had a 3.73 before and I'm much happier with the 3.23.