does it make sense to add 3.73 gear to my stock 5 speed TPI IROC? is it much of an improvement over 3.08 gear? will it hurt the car's overall driveability?

 

3:73 will make a noticeable differance.You can safely go with 4:11 with a 5 speed, but you'd be pushing it.I put 3:42's in my 305 TPI auto and was not satisfied. 3:73's will be in soon
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just be ready to shift

 

I had a 10-bolt 2.73 drum behind my 305 TPI and 700r4, but I recently upgraded to a 9-bolt 3.27 disk rear. After using it for a while, I'm thinking of ditching the 9-bolt and going with a 4th gen LS1 rear with the 28 spline axles, bigger disk brakes, and the 3.42 gear ratio. I don't want to go crazy with the gear ratio because I autocross and plan on doing some road racing... not that big into drag racing. Who knows, maybe I won't like the 3.42 ratio either.

Mike

 

Your current 9-bolt is stronger than the 4th gen 10-bolt. But its tough to find parts and gears, so....

 

I went from 3.08 in my TPI 5spd car to 3.42/zexel posi. Was a good combo. Mileage didn't suffer any, and the car was so much more fun to drive.

I just recently went to a 3.73/eaton posi setup just after I put my T56 in. Even with the lower rear gear I'm still 500 rpm less with the .5 overdrive 6th gear in the T56. I can't tell you how I wish I'd went to a T56 long.......long ago. The car is an absolute joy to drive now.

 

Went from a 3.08 open to a 3.73 posi in my wife's autox car.....

Made the car come out of the corners betters, although it meant relearning how to drive the car on course, but well worth it! Your rear tires will hate you though!

 

I know it amy be weaker, but I am afraid of the cost of a repair and I would rather have something a little weaker if it comes with much better brakes.

My tires already hate me with the 3.27 gears.

 

i just recently put 373 in my 305 tbi 5spd bone stock besides cf df clutch car and it makes a real diffrence my buddy has a 94 gt and he used to smoke me now we need a photo finish if w race do it youll be suprised when you slam into second and your car jumps sideways

 

'89 - '97 rear brakes will bolt right on to your existing package. But you'll need a '89-'92 parking brake setup.

 

to reply to the original post, 3.73 will work but you might be sorry. If your only drag racing it then you'll like them, but if you use it for commuting or driving on the highway sometimes, you wont.

To put it into perspective i had a set of 3.42s in my iroc. Cruising on the highway it was too high in the rpms for my liking. I since swapped in a bw 9 bolt 3.27. Dropped cruising rpms about 200 with very little to no effect on acceleration from a dig.

In the end it all comes down to preference. Some people like steep gears for racing while others want a more rounded package. Im one of the people falling into a more rounded package.