Benefits of going to 3.73 Rear Gear??

[jgutta2345]

I have an 83 Monte Carlo.
350 V8

Thinking about going to 3.73 Rear gear, just wanted to know what are the benefits of doing so?

Also do you guys recommend Posi or Non Posi?

Thx

 

[SScamino]

It's the best BANG for the buck acceleration you'll probably get. The down side is if your not running an overdrive trans that you'll be buzzing the RPMS on the freeway/interstate.

 

[monte7carlo9]

SScamino hit the nail on the head. I have 3.73's with posi in my 79 Monte with 26 inch tall tires and acceleration is awesome....but with only a th350 trans Im spinning 3000 rpms at 60 mph on the highway which is the downside. Im personally thinking of swapping to 3.42 or maybe even 3.23 just so I can drive my car on the highway with a little more comfort.

 

[pontiacgp]

personally I didn't even like the 3.42 I installed and went to a 3.08 instead. As for a posi if you're running a 7.5 I would run a locker. I had an Auburn 7.5 posi and blew up the pinion gears. The pinion gears in the posi are considerably smaller than the pinion gears in an open. With a locker you don't have any pinion gears or side gears to worry about but I would upgrade the axles

 

[maddog20_20]

I just put a 3.73 posi in my malibu and with the 200CI 6 cyl it will actually spin the tires and it made a huge difference in acceleration for sure. I don't have a tac so not sure of the RPMs at 60, but it is definately higher than it was with the 2.29s.

 

[dogsht]

If you want to build a fast and real street car. (As in you drive it further than the local car show or from street light to street light) you might consider upgrading the transmission to an overdrive unit. If you are going to stick with the three speed you would probably be best served with a 3.08 as if you are coming from a 2.14, 2.29, 2.41, 2.56 you will see et wise and feel a difference. It also will still cruise nice and won't buzz the motor hard or eat fuel like a non overdrive 3.73 gear. Another benefit of the 3.08 is that it if you have a two series carrier which is most likely it still a drop in with no need to get a 3 series carrier or adapter. If the carrier is not a concern you might also consider a 3.23 especially if you are running a taller say 27" or greater tire.

 

[khan0165]

I have a 700r4 (overdrive) transmission with a 8.5 posi rear.

with 3.42 gears, I run 2000rpm @ 60mph, and drop to 1800rpm with lockup engaged.

I speculate I would run around 2300rpm with 3.73 gears.

My 3.42s are great all around, but 3.73s would help me more at the track. Right now, I only run about 4900rpm thru the traps, and my power band is in the 5300rpm range.

 

[speedkills80]

I had a 3:73 7.5 10 bolt in my 80 malibu and swapped it out for a 3:31 posi 12 bolt. It still has plenty of push off the line. The biggest difference was on the highway. Much more fun to drive not having to listen to it wind up. If it were a drag car I would have stayed with the 3:73 but for the street...3:31 is perfect. It is what GM used back in the day as a mid range gear. Instead of the 2:73 or the 4:11 they used a lot of 3:31 gears. Works great with my Big Block and 4 speed. First thing to do is decide if you are gonna be racing or street driving and make your decision from there. Good luck!! 8)

 

[jgutta2345]

Thx for the replies guys.

What's going on is that I don't have an Overdrive transmission and I don't plan on doing any street racing of any kind. I'm just looking for a way to make my car faster. So based on the answers maybe going to 3.73 wouldn't be my best option. What would u guys recommend going to?

 

[dogsht]

Well you had two 3.08 and two 3.23 recommendations. I bet you get more.