I am in the process of throwing in a TKO600 in the car, and was hoping to change my gears. As it sits, the car has 3.73's in there. I hope to switch them out for 3.27's.

Has anyone else done this swap? If so, did you do it while you had the turbo on the car for both gear setups, and if so, did it change the way the car runs? better or worse in your opinion?

My car is a 302 with a MP T70 on it, as it sits, will spool quick and runs decent, but ill be damned if it runs out of gear up top way too fast with the 3.73s.

 

i'll put it this way, for all out ET you might be better off with the 3.73's but for the other 99.9% of the time you'll wish you went all the way to 3.08's instead of the 3.27's. I just went 10.45 with an auto and 3.08 gears

 

If you are running at the track 28" tall slicks / tires will cut the gear to a level where you should be able to make it through the traps. I have a TKOII (.83 OD) that will be in my coupe and I am thinking of running either 2.73's or 3.08's w/ 26" tall tires.

 

Did you have the 3.08 gear in the car when you had a 5spd? The TKO I have will have the tall 5th gear in it, so no need of going even that far with it. Does anyone have a chart or stats on the rpm/mph ratio for the 3.08's and 3.27s?

 

http://www.ringpinion.com/Calc_RPM.aspx

Try that one.

 

http://www.svtoa-atlanta.org/cgi-bin/trans.cgi

 

i went from a 3.73 to a 3.27 with the c4 and picked up almost 2mph

i think 3.08s may be in my future too!

 

I also did this swap. With the 3.73's I was on the rev limiter at the track. Much happier with the 3.27's now.

 

It all depends on what you're doing with the car. If you're into drag racing, it also depends on the power you're making, and the trap speed/RPM you're targeting. If you go too far the wrong way with gears and you'll be crossing the line in the middle of 4th gear, or, you'll be crossing the line way past your power band. You basically need to run it as it is, then determine where you want to be in the RPM's at the line, and make adjustments from there.

My old turbo car would 60' better with the lower gears, but I was running out of RPM on the top end. I ended up with 3.27's, and ran 10.55@133 with a 1.52 60' launching off the 2 step at 4400 rpm (and about 12 lbs on launch) with a 3550. It also made 732lbs of torque at the wheels which made those 3.27's feel like 4.10's.

 

Thanks for the input guys. Even though 3.08's are tempting, I think the 3.27s would suit me right now, as it will be a "light" track car, but more of a fun street car. Never know, if my car ever makes any power, i might drop down to 3.08's.