I have a 69 coupe 302, 3spd., 8in. rear and wanted to no what gears would be most efficient for me...my coupe is gonna be a daily driver and will drive it on the freeway some...I have no idea wat size gears are on it now and dont know how to find out...I want gears that will utilize my horsepower better and make it feel like its got more horses, new to this mustang thing and would like a little advice from the pros...
thanks

 

350's or 355's would be the best of both worlds for your set-up.[8D]

 

To decode your car, look at the Warranty/VIN plate. (See pic) than go to the following site to find out you gear ratio. A 2.80 or 3.00 rear gears will get you your best gas mileage. Crappy acceleration off the line, but killer freeway running.
http://www.vintage-mustang.com/topic...de/decode.html


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Ok thanks for helping my find out the gear ratio, it is 2.79:1

 

I have the same type mustang, but the stampings were partially misaligned at the bottom of the door panel info. I looked at the differential and in the area where the ratio is supposed to be, I have a '2T9'. Any idea of what this is?

 

2.79 is a great rear end for a daily driver and crusing the highway. As you increase the rear end ratio, ..up say to 3:40, 3:55, or even 3.70... yes it will feel more peppy off the light, but your fuel economy will suffer greatly. If your car is running 2300 rpms today on the highway, with 3.70s it will be running more like 3300 rpms... greatly increasing fuel useage and wear on the motor.

It's a trade off....

My advice is to save up and buy a T5 and then get 3:55 rear gears.

 

I went from a 2.42 to a 4.10 rear in a gm car. wish I had stated in the 3.08 range. standing start is great but aboue 50 the rpm is high and a gas sucker. It really depends on your cam. Mine did not come alive until 2800 rpm so the rear of 4.10 got there quicker. Really the wrong cam for street but from a 20 roll it's a blast.