How many of you guys run 4:10's with stock 10 bolt

**asthmamax11** · 12-14-2008, 05:42 PM

I keep hearing that 4:10 gears will kill the stock rear end like no other. What kind of luck have you guys had?

**JoshieDoom** · 12-15-2008, 01:50 AM

Local guy went through a set of richmond and motive gears before he went to the m9.

I suggested saving the money for a 9"

**rc74racer** · 12-15-2008, 12:35 PM

The gears will not kill your rear it all depends on how you drive it. I've had 410s in mine for over a year now with no problems. That being said for the $600 i spent on gears, full installation kit and install I wish I had saved the money for a 9" or 12 bolt. Don't get me wrong I love the 410s and it's a great mod just with my plans for the car I will need a rear eventually and I hate spending money twice.

**Firebirdjones** · 12-15-2008, 02:15 PM

You only get about 1 1/2 teeth of gear contact patch with a 4.10 in a 7.5 inch rearend. Thats where this theory comes from. The pinion is starting to get pretty small when you jump to the 4 series gears,,,and the small 7.5 inch ring gear diameter isn't enough to make up for it. You can sheer the teeth off if you try hard enough.

Why I don't recommend 4.10's in a 7.5 rear for the people I have built them for. 3.73 is about it,,,but I prefer to just step up to a 12 bolt before sinking any money in a 7.5

**cuzimoto** · 12-15-2008, 05:41 PM

Originally Posted by rc74racer

The gears will not kill your rear it all depends on how you drive it. I've had 410s in mine for over a year now with no problems. That being said for the $600 i spent on gears, full installation kit and install I wish I had saved the money for a 9" or 12 bolt. Don't get me wrong I love the 410s and it's a great mod just with my plans for the car I will need a rear eventually and I hate spending money twice.

How many runs have you made at the track and do you use sticky tires.

**rc74racer** · 12-16-2008, 04:51 AM

4 runs at the track on street tires.

**asthmamax11** · 12-16-2008, 02:04 PM

Originally Posted by Firebirdjones

You only get about 1 1/2 teeth of gear contact patch with a 4.10 in a 7.5 inch rearend. Thats where this theory comes from. The pinion is starting to get pretty small when you jump to the 4 series gears,,,and the small 7.5 inch ring gear diameter isn't enough to make up for it. You can sheer the teeth off if you try hard enough.

Why I don't recommend 4.10's in a 7.5 rear for the people I have built them for. 3.73 is about it,,,but I prefer to just step up to a 12 bolt before sinking any money in a 7.5

That's what I'll do then. I'll get the the 12 bolt and gears put in at the same time next year. Do 4:10's kill your topend? will my trapspeed be affected?

**Firebirdjones** · 12-16-2008, 02:36 PM

Originally Posted by asthmamax11

That's what I'll do then. I'll get the the 12 bolt and gears put in at the same time next year. Do 4:10's kill your topend? will my trapspeed be affected?

Doesn't really hurt top end in my opinion, not many places if at all for me to even worry about that. At the track you may notice your trapspeed increase slightly, depending on your engine combo. With a 6 speed and stock 3.42 gears,,,you can nearly get to the finish line in 3rd gear,,,with a stockish 6,000 rpm shift point you are probably going for 4th at the 1,000 foot mark,,,that won't get you optimum ET or MPH. Idealy you want to be in high gear at your shift RPM or slightly higher. A 4.10 with stock 26 inch tall tires and stockish power levels will get it close.
Recently ran my wifes car with stock 3.42's,,,with a small cam that allows ,6500 rpm shift points,,,,I could cross the finish line in third only bumping the rev limiter about 3-4 times, (rev limit set at 6,600) which netted me 109 mph,,,tried a run shifting to 4th right at the finish line and it got me 109.91 mph. You could say this car needs a gear in it.
Even a stock LS1 will respond to a gear change.

**Tickwomp** · 12-16-2008, 05:32 PM

4.10s was my first mod. I thought it was good bang for the buck. Seems to really wake the car up. I'm saving for a new new rear end. Really looking forward to dropping on the hammer with some sticky rubber!

**Wesman** · 12-18-2008, 02:40 PM

I have 4.10's in my stock 7.5" 10 bolt. Also have a MAC girdle on it for extra support.

I don't run drag radials or slicks, just 285/40/17 Nittos. Had it to the track a few times, run it on the street all the time, no problems as of yet. I also try not to abuse it though, no 6K clutch drops or anything like that.