1968 Chevy chevelle engine, I am trying to find the perfect gear set for the rear.?

[Vin]

It has about 325 horse. I want something that has both enough power on the highway but also at take off. 3.08? 3.42?

Let me know what you think is the best for my engine......

[JAY]

All depends on the transmission you settle on using. You can use a steeper gear like a 3:73 or something if you use a transmission with overdrive. People above me have some good info. If you stay with the transmission already in the car, I'd look into something around 3:42 or less.

[vtx.1800retro]

308 If Its An Automatic, 342 If Its A 4 Speed, 410 If You Want To Rip The Pavement Up, 273 If You Want Mileage, Best Way Is To Have An Overdrive, And Run A 373, Both Mileage And Power.

[Hall + Oates]

i'd get a 3.73 posi.

[paul h]

3.55 or 3.42 is a good compromise between acceleration and economy especially if you drive highway a lot. A 3.73 ratio is a little steep for lots of highway driving and will cause excessively high rpm's for good fuel economy but it's good for street use and low rpm response. Personally, I'd go with 3.55 or 3.42.... My 69 Charger RT 440 had 3.55 gears and got 20 mpg on the highway if I drove it at 55 mph.

[ms_beehayven]

The higher numerical ratios will give you more low end grunt...ie the 3.73 (and 3.90's, 4.11's, 4.56's) gears will launch you quicker than the 2.73 will but you'll pay a price in fuel mileage. The 3.73 will give you RPM's around 3000 at 65 MPH with a Turbo 350 transmission while the 2.73's will be down around 1700 or so. You can see your fuel mileage will suffer at higher road/engine speeds. Here's how I solved the problem in my 67 Nova....3.73 gears with a 700R4 automatic transmission. The combination of the lower first gear in the 700R4 (compared to TH350) and the 3.73 gears in the rear end gives me some impressive launches from a dead stop while lowering engine RPM's at highway cruising speeds. It's a compromise.

[Gordon S]

3.55 to 3.73 is a good all around final ratio.