2.73 to 3.08 gears?

[big gear head]

If you want to drive on the highway then I would at least go to a 3.42.

 

[flht99b]

I've posted this before so a search of this site would have brought it up.
Google Tremec Gear Ratio Calculator. This way you can see how tire diameter, gear ratio and trans high gear ratio change from at a given speed.

 

[CorkyE]

If you want to drive on the highway then I would at least go to a 3.42.

Agree, 3.42 seems to be a sweet spot with a TH-350 transmission, GM put a lot of Z-28's out the door that way. I had 3.42, went 3.73, and it wasn't fun to drive on the interstate. I've since switched to a 700R-4 transmission and it much better.

 

[rburrow87]

I was running 3.42s with my TH350 briefly before I yanked it out to go to a manual and it wasn't bad at all cruising at 65 MPH. I have some small 25.7" tires (245/45r17) so it was 3000 RPM +/- 200 with the converter slippage (2400 stall 10" converter). I could see it being unpleasant if you have an especially loud/droney exhaust or if it dumps before the axle, but really any kind of highway cruising will be unpleasant like that.

 

[Z28SSRS]

I think 3.42's work perfectly with a TH-350. I've had fun driving my bought new '78 Z28 with that combo whether it was street driving or freeway for coming up on 42 years. It gives what I consider acceptable performance in acceleration and in freeway driving never runs higher than 3,500 rpm on an extended basis.

 

[tom3]

Whoa, 4:56 with a 350 auto trans? Plow a field with that gearing.

 

[80sz]

^thats what I said. Holy that had to be snappy

 

[JOEY72camaro]

Whoa, 4:56 with a 350 auto trans? Plow a field with that gearing.

^thats what I said. Holy that had to be snappy

haha right only drove the car up the street didn't even get out of first gear doing body work on it right now guy I bought it from just put an engine and trans in it so guess he never drove it I would of thought the trans was bad if I never got the rear end rebuilt

 

[Zspoiler]

Chevrolet got it right in the Z-28 Turbo 350 with 3.42 gears .It gives a good compromise for a performance street car. With good acceleration and in the sweet spot for fuel mileage on the freeway.