dizwiz24

Ive heard of people saying that 4.10's (despite 6th gears .50:1 OD ratio) is simply too much on an LT1 car. Plus also, we know that causes you to actually have to 'add' another shift from 4 to 5 on the 1/4 dragstrip which slows down times.

Well, what about say 3.73:1.... ? Seems to me that would be the perfect compromise. Some calculations show a ZF6 with the 3.73:1 ratio puts drive ratios (trans gear ratio * rear axle ratio) around that of a corvette z06.

Or is it not enough to really be worth the effort?

I have the stock 3.45:1 ratio.

The Green Rocket

Three questions:
1) What is your intended purpose for the gear change? Drag racing?
2) What engine modifications, and what rpms will the engine see?
3) Have you had times in performance driving where the engine was at the wrong rpm for the manuever - when you would have prefered to have already been in the next gear?

For my engine I set the rev limiter at 6,800 rpm, (actual shifts at 6,400/6,500 rpm) and I have 4:10 gears. With the 3.45 gears drag launches were tricky, no problems with the 4.10 gears. Also, with the 3.45 gears I was just shifting into fourth gear practically at the same time I was going through the lights. So for the drags the 4.10 gears are great. On the street the 4.10's are fun too - my Hot Lt4 has enough torque to easily pull from a standing start in 2nd gear, and then pull to almost 70 mph before the next shift. That is too much fun, and it puts the shift points at good speeds for fast road work.

Thomas

neat

The 4.09 is not too much gear. I don't think you'll find one person who has actually done the swap and regretted it. The people who say it's too much gear haven't ever actually driven a car with them. They are looking at numbers and charts, and ignoring the people that have done the swap and love it.

2200 RPM is about 75 MPH with the stock tire size and the 4.09 gear. You'll probably get better mileage overall because you'll be able to pull it into 6th gear at 55 MPH.

The only reason to go to a taller gear from the 4.09 is if you start to trap in excess of 130 MPH at the drag strip.

The cars should have come from the factory with the 4.09 gear set.

cv67

With the others..hardly a difference between stock and 3.73

96GS#007

As an "fyi" there is both a 4.09 gear set as mentioned above and a 4.10 gear set. You will want the 4.10s.

4.09s have a collar welded on the pinion shaft. The pinion is actually from an Isuzu light duty truck.

4.10s, also known as the "Viper gears" do not use a welded collar and are stronger as a result.

Just a note for all.

I had 4.10s for many years. Great fun on the street but in my case they just didn't work out on most road courses that I ran or currently run.

96 lt-4

I could run through the 1/4 in third gear with the 3.45 set (LT4).With the 4.10 gears I have to change into 4th.
I actually wish I had the stock gears in mine now.I make more than enough hp/tq to not need the extra gear now.I am constantly changing gears around town.So I just go 1-3-5 most of the time.

OldCorvetteFan

I've got 4.10's in mine, and I much prefer it - even if it's just for street. The engine seems to like it a lot more than the stock gearing.

Steven

BlackHarleyMan

I run 4.09's and I like them, but I'm in the process of changing out to 4.11's in the next few weeks. I'll let you know how that works out after the fact!

R/Noland

StealthLT4

Haha, doubt you'll notice much of a difference between 4.09 and 4.11's

Also, nice avatar

LTxDave

For a stock(ish) LT1 or LT4 car running quarter mile, the 4.10's work well. For your supercharged LT1, I'd probably leave the 3.45's. I plan to swap back to 3.45's when my supercharged 383 goes in.

Aardwolf

Whatcha running for the road courses?

mnstrlt1

in the mustang camp, the "great compromise" is a 3.73:1... because it allows the end user to have a larger window of horsepower goals...

the 4.10's and a supercharger ='s a lot of time smoke! Serious throttle modulation off the line to get the combo to behave.

I would go 4.10's if I had a ZR1.

C4DC

I went with 3.90 and am happy with them. Enough to feel the difference from stock, better #s at the strip, and ok for open road racing (which the 4.10 seemed to be looked down upon by the road racers). My city mileage got better by a couple MPG and the hiway went down a couple. It is nice being able to use 6th at 40mph.

pologreen1

WOW

96GS#007

I went back to the stock 3.45s.

Frankly I got tired of all the shifting just to be able to do with 4.10s in 5th what the 3.45s do quite well in 4th. About the only benefit of 4.10s was exiting slow corners in 2nd.

LT4BUD

Wow, 5th gear, you must be really running some high speeds....100+??

Actually the biggest benefit of the 4.10's is in first gear where you are putting over 18% more torque to the rear wheels...

I love mine for the way I use my car (LT4).....no regrets



EDIT.....back to OP, the 4.10's are more popular with stock LT4 than stock LT1 related to the higher RPM operation, but on modded engines this difference would be negated. You really need to look carefully at your car and how you plan to use it...

Ruby6spd

My car is 100% street driven with 4.10's, full length headers, no cats, and a pcmforless tune.

This side of going to a new cam, better flowing heads, adding cubes, I couldn't be happier with the way the car runs.

Much quicker/snappier off the line that stock and sounds great.

Again, this is a pure street car and in my opinion is a perfect combo that is deadnuts reliable.

STL94LT1

I love my 4.10's!! Having made that statement, I would keep the stock 3.45's with a supercharged engine.

CAJUN C4

By far the Best Bang for the Buck.It Changes the whole personality of the car.Your clutch will last longer under normal driving conditions and the Fun factor will go way up.

Red Rocket

5th gear is for driving on a road cruise to Bowling Green. Hit the
rev limiter in 3rd gear at the 1/8 mile tracks (98MPH) and 4th gear at the 1/4 mile tracks at the traps with my 4.09 gears(126MPH)

If your lined up next to a new Z06 at the stop light what gear would you want? A 3.45? Don't think so. Put on a set of Hoosier DR's and the 4.09-4.11 gears and you won't look back.