Hello,
I got the 4.10s installed. They don't wine I started doing the proper break-in for the gears but couldn't take it any longer at 350 miles. So, I go to a disserted road, estimate the 1/4th...then blast off. The tires did spend a little but hooked really well.....BUT, I had to shift into 5th.
What can I do other than going to a 17X11" rim to keep this from happening.
Would going to a 285/40/17 BFG DR in the back solve this?
Other than the concern mentioned above, I really like the gears.
Thanks,

Tim

 

what are you shifting at?

My stock LT1 with 4:11's i'll cross the line in 4th comming up on the 5th shift on 275/40/17

 

Shifting between 64-6500 rpm

-Tim

 

I was trapping 120 w/4.10's in 4th gear on 26" tall tires
Go to the track and est. your 1/4 there

 

Thanks for the replies.
Your car is getting somewhere fast. What was your shift point?

-Tim

 

That's the issue with 4.10's and an upped redline. Thus the reason most people with any decent mods go with a 3.73 setup out back due to this exact reason.

 

Hate to break it to you but you're not running that fast in the 1/4. 6500rpm + 4th gear + 4.10s on a 25.7" tire equals 122mph. Keep your gears and tires and take it to the track.

I went to 4.33's to go out the back door near redline in 4th, and if you shift at 6500rpm, your current tire/gear combo should be very close to optimal.

 

A 17X11 rim or a 285/40/17 isn't going to change you "gear ratio". They both end up having a diameter of approximately 26". You'd need to step up to a 27" or 28" diameter setup to stay out of 5th gear.

Here's a link to a gear/speed calculator:

http://www.f-body.org/gears/

 

I bet your "estimated 1/4th" is off, take it to the track as mentioned.

 

Thanks for all the help and advice fellas.

I'll followup on the info as soon as I can.

-Tim