I want to get 3.73's for my 92 RS and what kind should I get .......what series carrier and all that......also....do I have an electric speedometer???? If so, how can I get it to where it reads the right speed?

 

You probably have 2.73 gears stock, so you'll need gears for a 2-series carrier. I recommend Richmond gears...they make a little more noise but they're much stronger.

Your speedo is electronic. How to make it read correctly with a gear swap, I don't know.

 

Seems nobody knows how to correct that. Could you make the speedometer not electronic or would that be too much trouble?

 

i think, THINK, that the electronic speedo is still driven from the tranny where the cable goes, by gears. if you get the right gears, the electronic sender, VSS, should be corrected as well.

I THINK. do a little searching, when i swapped gears i bought an aftermarket VSS sender, and an aftermarket guage. thats why im not quite sure.

 

well, I know the 86-90+ firebirds electric ones use gears there so unless they changed it in 92 it is still the same thing.

 

I have the Richmond 3.73 gears with an Auburn limited slip diff. I'm having the same dilemma with the speedo reading 15mph too fast at around 80 mph. Dakota digital has a speedo calibration box that should correct the speedo. It costs around 80 bones. Or you can also change the speedo gears in the tranny.

 

Somebody said 3.73's were too steep for a stock TBI but what's your opinion? Also, where can I get that calibration box at?

 

Somebody said 3.73's were too steep for a stock TBI but what's your opinion? Also, where can I get that calibration box at?



That's true for a stock engine because the factory cam is good for low to mid range torque. My engine makes it's power in the mid to upper range. The 3.73's compliment that and gives you eye popping acceleration. You can find the calibration box at http://www.dakotadigital.com/Detail....rtNumber=SGI-5 or there's a more expensive one here - http://dragonaero.com/SpeedChangerPage.htm

 

3.73s will give it ALOT more off-the-line grunt, especially with a low end torque kinda cam.. go for it

 

Kingtalon is right. Also the 3.73's will be great for your car. It's true that the stock tbi cam sux, but the nature of the tbi is that it doesn't die off in the upper rpm's like tpi does so 3.73 arent really too steep even for a stock engine. The stock tbi cam will probably peak at just past 4k rpm, but it stays flat until even after 5,000 rpm and doesn't really drop off so you can take advantage of the 3.73's.

 

25THRSS is right but I think he was talking about built TBI's to TPI's in ease max rpm power. Because a stock TBI has a serious problem with high RPM unless it is cammed and pretty much stops accelerating past 4k. When it is cammed a TBI rev's vary well and would have no problem 'out reving' a stock TPI setup.

 

https://www.thirdgen.org/techbb2/sho...ghlight=dynoed

There is a dyno of a stock 305 tbi with exhaust and a chip. Everything else stock, for reference.

 

Eye popping, yeah, more like tire popping.

I can break em loose at 70+MPH by accident if i step down too hard. 3.73's are pretty harsh, especially if your actually making some power.

I like it

 

i always read, 3.73's for manuals... and 3.42s for auto.... might want to look into that a little more. that's just what i read. i haven't had my gears changed yet.

 

On 4th gens with the .5 overdrive on the t56, that might be the case, but most t5 overdrives are similar to the 700r4 so I don't think it would matter which transmission you have. Ideally you want to have the right gears so that you cross the finish line right at or slightly past your peak power in 1:1 regardless of what transmission you have.

 

i love my 3.73s, i went with those because ill be going with a 350 and LT1 cam setup in a few years but they took about a half second off my ET (15.97 to 15.29 with 3.73s, posi, crank pulley, and tbichips.com's Stage 1 chip). As for the speedo, just go to the dealership at get some new speedo gears (2). www.700r4.com has a calculator that will tell you which ones you need. Do a search and you can get the part numbers.

 

Ok I have 3.27's I am thinking of swapping them to a 3.73's. My friends say that I will not see or feel that much of a difference. They say go 4.10's. But I do some 200 mile trips every so often and would like to keep the rpm's from soaring. I have a 87 GTA with a 700r4. Mods in sig.

 

Ok I have 3.27's I am thinking of swapping them to a 3.73's. My friends say that I will not see or feel that much of a difference. They say go 4.10's. But I do some 200 mile trips every so often and would like to keep the rpm's from soaring. I have a 87 GTA with a 700r4. Mods in sig.


The last thing you want to do if you do long trips like that is put 4.10 gears in there. With my 3.73's in 5th gear (.63 ratio) the engine is revving 2500rpm doing about 80mph. Fuel consumption will change big time.

 

That is what I was thinking

 

Iam also thinking about putting 3.73's in my 700R4, my question is, how hard is it to do this, is it possible to do with just your everyday tools, I herd someone talking about how you need a press to do this??? Also same question about a TransGo Shift Kit. Thanks

 

I wouldn't do it myself. You cant do it with common tools and you must be right on or else your gears will be ****ed! Just pay a professional to do it for less than a couple hundred. It's worth it to have them set up right or you will regret it.

 

Thats kinda what I figured, My Grandpa races and he has a shop very close to where I live I can have him do it for free, that will be very easie considering he does have a hoist. Iam just sick of always relaying on him for it seems like everything, you know? What about the Shiftkit?

 

You can do the shift kit yourself. It's complicated, but it can be done and is a very good mod for an automatic. Transgo is the way to go.

 

Cool Thaks man. I will do that very soon, This weekend!! Thaks.