79nova

i am building a 1979 nova with a 2005 5.3 with drive by wire, all stock will be running a th350 transmssion, need to deside on a good all round gear, will be driven on the highwayand used as summer daily driver /weekend car may do some dragracing with it too, been looking at moser 9 inch rear end for it,

Doug G

3.50ish
For longer cruises and/or better MPG 3.20ish

02ws.sik

3.50 or 3.73

Moter

iTrader: (20)

http://www.corral.net/tech/gearcalc.html

Try this site

Rick Speed

iTrader: (55)

I was going to say 3.23

itsslow98

iTrader: (18)

3.55s would be as low as id go. obviously if you were that concerned with gas mileage you wouldnt have gone with a th350.

gofastwclass

iTrader: (2)

Agreed. Lose the TH350.

Get a 4L60E (computer controlled transmission with .7 overdrive) and run either a 3.2x through 3.5x but nothing steeper than 3.5x if economy is a motivator. The 3.2x will give you more economy on the expressway with a little loss in acceleration from a stop. The 3.5x option will give you more from the stop while trading top speed / cruise economy.

I have a 3700 lb car (without me) with a 4L60E and 3.23 (factory) gears that gets 16 - 17 city each tank with me beating on it regularly.

79nova

i am using th350 because was in my other nova, has only 3000 miles on it, and if i want gas mileage i will drive my 78 nova it has 5 speed over drive in it thanks for all the help guys

tsnow678

iTrader: (3)

A 3.42 gear is an all around good gear. Being your limited to three gears and third gear is 1:1, a 3.42 would be ideal. I had a 4 speed in my car with 4.10 gears and it was miserable to run on the highway. After I changed to the 3.42 I could actually drive on the highway without the old lady running off at the mouth. I have since swapped out the engine/trans to the 6.0/T56 and have left the 3.42 in and this car pulls good throughout each gear. Probably not ideal for the 1/8th drags but running down the highway I am turning 1700 rpms @ 70mph in 6th gear.

gMAG

iTrader: (1)

With a 1:1 final gear in the 3.50T, I wouldn't go any more than a 3.23.

Moter

iTrader: (20)

How tall is the rear tire. Its makes a difference

N20zuki

My question is since your keeping the drive by wire, what are you going to do for the kickdown cable for the TH350....?

gofastwclass

iTrader: (2)

Good point.

...and another good point which gets me back to my opening statement. I completely understand using what you already have but...

As far as fuel economy, that is directly proportionate to driveability. I'm not saying fuel economy is the end goal but if driveability is high on the list, economy will automatically follow. Besides you don't want to cruise down the highway at 3100 RPM at 55 or 60 MPH (been there) because of poor transmission / gear choices which all goes back to my previous post.

Just something to think about.

futureuser

iTrader: (1)

I'll bite. Looking at a nine inch? Not worth it unless cheap. Money better spent on overdrive. TH350 is terrible by todays standards. If you insist on the th350, I would use a 3.08 with a 26 inch tire, or a 3.23-3.42 with a 28 inch if you want to drive on the highway. Highway traffic nowadays isn't 60mph anymore. If more interested in dragracing than highway, go with 3.42-3.73, but highway will suffer. No matter what gear you choose, you will be compromising, unless you have a massive amount of boost.