[demarques_191]

I'm about to install the used rearend with 2.73 ratio i got from the junkyard until i can get the other rearend back from the shop which will be 3.42 posi, 12 bolt. I have a bone stock 350 c.i and a th350 mated with it. I was wondering would the 2.73 be better on gas mileage or hurt gas mileage??? I have always heard the 2.73 will make the combo sluggish/ a complete dog. Or will it give me exceptional fuel economy with the 3 speed th350 and have decent driveability??

[poncho62]

I had that setup in my truck (51 Ford) for a while....got 20-22 mpg....Now have 3.55s and get considerably less....didnt seem sluggish

[xxllmm4]

Whats your tire height and vehicle weight?

[demarques_191]

well thats what im looking for for the time being... better gas mileage but i dont wanna have to floor it for it to get up to 60 mph when merging unto the highway lol

[MouseFink]

I replaced the original 3.08:1 carrier with a new 2.69:1 Safe-T-Track "Freeway Flyer" carrier in a '63 Pontiac Bonneville. I ran that gear for about a year and when my wife drove the car, she made the comment that she thought there was something wrong with the engine because it did not accelerate like it did before.

The '63 Bonneville actually got worse gas mileage with the 2.69:1 gears because the engine was laboring all the time and the engine took longer to get up into torque range. The only reason I installed the 2.69:1 gear was because it was a new unit and it was a Safe-T-Track. I replaced it with a good used 3.42:1 one legger as soon as I found one.

[big gear head]

It will run fine with the 2.73 and TH350. You will love it on the highway. There were probably millions of cars built with the same combination in the '70s and '80s.

[27Tall T]

I had a 2:73 and a 350 with a turbo in my deuce and I have to say it was not sluggish and managed to get 25mpg consistently. Did I mention that I was also pulling a fold down fiberglas/canvas fold up trailer behind it?

[454C10]

A 2.73 with a th350 will be great for the highway. But just OK for relaxed driving around town.

Years ago, I had a 350/350 and 3.08 gear combo with 30 inch tall tires in a 4000 lb ride. One the highway I was wishing for a lower numeric gear and around town a higher gear. So always a compromise with a 3 speed trans.

Maybe a 4 speed would do trick.

[demarques_191]

the wheels are 265/35/22 ... its a c-10 1978 chevy truck, big ten.. lwb... not sure of the weight of the truck

[big gear head]

Don't expect neck jerking performance off the line, but after you get going it should be fine.

[454C10]

29.5 inch tire. Do the wheel spin when the truck is stopped?
Should weigh around 4000 lbs.

[AutoGear]

Just go to Bonneville or the Texas mile...LOL
It'll be fine. If you like the economy then put in a TH200-4R with your 3.42 axle; it'll make for a nice cruising truck with decent off the line performance. The right converter for either axle is key to making this reliable and comfortable to drive