Hey Guys, I'm thinking about a gear change in my 66 with a 289. right now it's got a 3:00 gear in her which is great for mileage and driving around but I was thinking about a 3:25 gear. How much would this change the mileage and performance? I know some of you here think a 3:50 gear would be better.....is that something you'd feel in the seat of your pants?

Is your car automatic or manual.

I think the 3.25 is ok for normal driving. This would allow you to maintain highway speeds on hills and you would still achieve reasonable mileage.

The 3.5 is a better choice if you like a little quicker acceleration. My opinion is this ratio is a little too low for continious highway cruising with a standard engine. An engine with a slight performance cam would probably like the 3.5 ratio.

3.5 is a great ratio for cars with an overdrive transmission


If you change the ratio, the speedometer gear will need to be changed.