I have a 92 Z28 with the 700R4, it's a daily driver but I want the best performance from it. I am also putting in a B&M Stage 2 Shift Kit, and then later on a ZZ4 Crate engine... So what do you think would be best?

Right now the only mods on it right now is a full exhaust.

-Peace

 

If you plan on leaving the TPI on it, don't go past 3.42. (No such thing as 3.43 incidentally...)

 

listen to sofakingdom

I used 373's with tpi and a 5 speed 1st gear was usless but on the plus side 4th and 5th with 373 pulls real nice above 50mph. but 373's get tpi wound up way to quik. Not sure how they would be with a automatic though.

 

If a daily driver - and driving in the rain - stick with 3.42's. I have a shift kit, vette servos, and 3.42's, and it's all I can do to leave a red light in the rain without spinning like mad. On the 1-2 shift, my tail is all over the road. Plus you be saving a tad on gas.

 

Throw away the B&M shift kit and get one that actually fixes the factory compromises instead of relying on brute force.

Trans GO kit is superior on many levels.

As far as rear gear goes, if you have a 3:23 already and its in good shape, leave it alone, if you have lame 2 series gears, upgrade to a 3:23 or 3:42 setup and dont go any further if staying TPI.

later
Jeremy

 

- Unless you're going for all it's worth, one step is a very minor gear change. - And YES, the B&M kit sucks. It's not the proper way to do it, the decrease in trans life will show it.

 

yea... 3.42 mistake, but what shift kits would you recommend.. links?

 

transgo or superior - plus either a vette or a billet servo

 

All this ragging on the B&M kit makes me wish I had something different lol. But the PO installed it, so I'm kinda stuck with it for now. I just had a fresh rebuild, and I'm not racing, just daily driver - so maybe she'll hold out for a while.

 

I'm looking at a gear change as well. I'm running a 350 with world products sportsman heads, big cam 850 Holley, etc. etc., with a Turbo 400. If my main concern is racing, what size gear would you guys suggest? What else would it take to hold up to some major horsepower? It's not my daily driver, and I really don't care how it whines on the expressway.

 

i've had it all on my Irocz.... 2.77's then 3.27's in the 9 bolt, then 3.42's in the new 10 bolt. my favorite gear is by far the 3.42's. good enough for daily driving, but the perfect amount of gear for the TPI setup.

first gear goes by in a hurry and it helps that second gear drop. and it really opens up third gear from 65mph on

 

How hard is a shift kit to install?

 

There is no "best gear" for any one car. The best gear is the one that suites the engine power band and the intended use of the car. - I'm running 3.73's now, but with the new motor and the 6 speed I'll probably be going to either a 4.10 or a 4.56.

 

I wouldn't go lower(numerically) than 3.73's. I go thru the traps at 53-5400 rpm with my 3.73's, which is perfect for a modded tpi motor.

You will want more power later, so change gears only once.

 

RECENT UPDATE:

I do plan on modding my TPI a lot, with bolt-ons...

So 3.42s or 3.73s?

 

On my stock 305TPI I gained 3mph and dropped .5 sec from my ET going from 3.23 to 3.73 gears when I was an Auto.

With a T5 and 4.10's, ET stayed the same but I picked up another 4mph.
I didn't make it to the track with the 3.42's I have now.

For your car, I would go with 3.73 gears.

 

Tried both. I prefer the 3.42's. Pulling 2800 RPM on the highways with 3.73's gets boring. And with that deep 1st gear ratio in the 700R4, the 3.42 gives plenty of oomph down down low.

I wouldn't bother changing from a 3.23 to 3.42 though. Not enough difference.

 

I think I have those 2.73s or whatever they are.... the stock ones.....

 

When I went from a 7.5 too a 8.5 rear in my monte my gears went from 3.73 too 3.42.I noticed very little power difference down low(car really got faster because I wasn't spinning till 35mph)but the top end is way better if I stomp it at 60 on the highway.I still have some traction problems with MT drag radials and full suspension with 3.42s and I have a zz4.Unless you run around town with drag radials I wouldn't even bother going more then 3.42s.You will have traction problems and the car will just be that much harder to launch.My freind went from 3.42 too 4.10s with a zz4 and he only picked up .2 tenths in the 1/4mile and the car is a dog against mine up top after 65mph.Though the car might feel a little faster out of the hole with 3.73s it will only give you a tenth or so in the 1/4 mile if you can get the car to hook up.3.42s Invest in a good converter instead of the 3.23-3.42 swap.A good stall like edge,or percision will make more difference then the gear swap.

 

3.42 dont go with the 3.73.

THe TPI will not work in a power band to take advantage of those 3.73 gears.

I have tried both. WITH A TPI 305 5 speed car. The 3.42 is faster. PERIOD.

 

i have a 1986 i-roc z28 im still figuring out what gears i want. im putting a 412 small block maybee pretty close to 650 HP. what do you guys think??? i was thinking 4:10's.....

 

depends on the trans you plan on using.

 

3.73 would be perfect with 28" tall tires.


or 3.42 with 26" tires

 

Yea thanks, i Have a A 700 R4 with a stage 2 shift kit.

 

Stay with the 3:42 and enjoy the little extra milage with the 700R4. Keep the rpm's manageable until you put the hammer down.

 

if only gm made 3.55's! but i vote for 3.42's

 

I thank everone for the imput, i went ahead and ordered 3.73 cause im really not driving on the streets if anything ill be towing my car to the track.

 

hell i would trade my 3:73's for 3:42's