MI-Z/28

I'm debating getting 4.10s. Car is setup with the following:

• Manual
• LS6 intake
• 1 7/8 LT's
• 245 rear tire with 300 AA rating
• 10 bolt rear end
• rear LCA's with relocation brackets

Car is a daily driver. I do not go to the drag strip. If I do it will be a once or twice a year event, and I would not be running DR's. May go to an autocross event once or twice a year. So my questions are:

• Are 4.10's too much for a stock cam?
• Is a 245 tire too narrow for 4.10 gear? Will I be spinning too much on every shift?
• With a 245 street tire and lack of trips to a drag strip is the 10 bolt still too weak?
• Should I just save my money and time and keep stock gears until I add a cam or get a new rear end?

V68Sweep

I'm not the one to answer the 4.10 and cam question, but:

Yes, 245s are too narrow for what you have, especially with 4.10s. I have 275s with 3.42s and I need to go wider to not burn out like crazy in 1st (I'm making about 360whp w/ mods in my signature).

Your 10 bolt will eventually brake if you add much more torque.

If you can afford a new rear end, do it. I would if I had the money

tarpley1

i just put 4.56's in my 02 hawk, pro 5.0 shifter, and a southbend clutch. otherwise my car is completely stock, and i love the .56's
gears are by far the best bang for your buck in a small CID engine period. (my opinion)

go 4.10's you wont be disapointed.

FirstYrLS1Z

iTrader: (4)

I'm 4.56 auto w 315s',do 4.10s.
even with LCA re-los,245 tires are too small. since the car came with 275s',why did you go smaller ?
for autocross you're gonna need some sticky tires or your ***-end is gonna be sliding/spinning out for/at every turn.

MI-Z/28

Z28 came with 245 on all 4 corners from the factory. Only SS came with 275 all around.

MI-Z/28

So you put 4.56 in a 10bolt? Did you do anything else to the rear or just the gears?

02T/A-WS6

iTrader: (4)

I have 4.10 in a stock 10 bolt with no issues. I have done some autox and 1/4 mile with no problems. With the 4.10s I do 74 mph at 2k rpms in 6th gear. I doubt you with have any issues at all with 4.10s in terms of it breaking. The majority of people that break their 10 bolts is when they put a sticky tire on are launching the car. I slip the clutch from 3k rpms at the track so there isnt as bad of a drivetrain "shock" like if you were dumping the clutch. The way I look at it is the spinning the tires after you let out the clutch is not hard on the 10 bolt because there is no tire "grip" i.e. not as much stress as if it was hooking up. If you are full throttle all the time you have be goin through tires, but it you roll into the throttle you can control whether or not you will be spinning...all on how you want the car to react.
Also I wouldnt think the cam would have anything to do with cam you have in the car soooo no worries


My vote....do 4.10s and dont look back. I abuse my motive 4.10s and have zero issues. Over 50 passes at the track and a few autox's, plus some very "spirited" street driving haha

02T/A-WS6

iTrader: (4)

just left these tonight actually haha....like I said "spirited" driving or abuse which ever floats your boat

FirstYrLS1Z

iTrader: (4)

I stand corrected on the stock tire sizes,yes 275's were SSs'

4.56s' and an Eaton posi.
Been working on GM rearends since the 60s',yea I'm old.
In 2003 OEM rear started to a growl,recognized it as a carrier bearing,built up a rear with 4.56s'(picked up at a swap meet for $25 used) and picked up an Eaton posi at Summit in their bargain/returns corner for $250(only center pin was missing) and the rear I picked up at a swap meet for $125 complete less gears and carrier. Put that rear in 2007,4 years after the 'growl' started and been running it ever since.
Even made 4 trips to Florida from Ohio with the 4.56s'.
I'm planning/in process of rebuilding the OEM 3.23 rearend for putting back in,but the 4.56s are way too much 'fun'.

01ssreda4

iTrader: (96)

4.10s without question.

HioSSilver

iTrader: (8)

3.90's are stronger and quieter than 4.10's. 4.10 are a bit much for these cars.

ws6outlaw

if you get them done right they are great. LOTS of take off! i was lucky mine don't make a sound. my car really responded to them. you will love them..i would go wider on the tire but that depends on how "aggressive" you like to drive. go 275 or something like that. i think you can even go 315's with a stock rear if i'm not mistaken.

FWIW, i have an m6 with 400 rwhp

My6speedZ

iTrader: (18)

4:10's all the way. Look in the classifieds for some used 10 bolt stuff, i got my whole carrier unit and gear set for 250 bucks, wines just a bit but has held up well.

I have 245's in the back with 466rwhp and they blow off all the way threw second. Sometimes they will even spin in 3rd a bit. However, thats ok with me and i only drive on the street and this saves my 10-bolt until i can get a nine inch.

When you get them just make sure to take it some place that knows what they are doing or they might end up screaming while your driving.

01ssreda4

iTrader: (96)

I have never put in a set of 4.10s that made noise and never seen a set break. And have never heard anyone I installed them for complain that they were too much.

tarpley1

sure?, it needed rebuilt anyway, ill just get the fun out of it while it last, i refuse to put any more money into a 10bolt, let er' blow LOL.
Highway driving is minimal in my area anyway.

as far as that being the only mod, MORE is on the way. but i do NOT regret 4.56's on a stock car at all. its a blast you just got to shift like a ****

MI-Z/28

Ok, so if I pull the trigger on some 4.10's I'm hearing that I should also pick up an Eaton posi and a new carrier bearing? Is this it, or is anything else recommended when doing the install?

02T/A-WS6

iTrader: (4)

You dont need a new eaton posi....just get the 4.10s and dont look back. You wont have any trouble with them on 245s or even 275s which is what I run.

02T/A-WS6

iTrader: (4)

yea an eaton posi is almost 500 bucks... the gears are around 180. Spending that much already puts you 25% towards buy in moser 9inch, which you have no need for at this point.

MI-Z/28

I'd like to do just the gears, but if it's recommended to buy something else to support them I will consider it.

02T/A-WS6

iTrader: (4)

the "weakest" part of a stock 10 bolt is the ring and pinion, not to mention the over all size which is 7.5 inches as opposed to 9 inches. When people talk about blowing their stock rear its the teeth on the ring and pinion. The posi unit isnt the issue. Im a "play it safe" kind of person and didnt see a need for them. IMHO its a absolute waiste of money....just tryin to keep some ching back in your wallet. My plan was to put 4.10s in and drive the ***** off the car and if it blows then I would get a new rear.... still waiting though haha