Notices
C4 ZR-1 Discussion General ZR-1 Corvette Discussion, LT5 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track

Who has made the switch to 3:75 gears?

 
Old 11-18-2018, 08:58 PM
  #1  
1985 Corvette
CF Senior Member
Thread Starter
 
1985 Corvette's Avatar
 
Member Since: May 2004
Location: Jacksonville Florida
Posts: 4,261
Thanks: 0
Thanked 50 Times in 38 Posts
Default Who has made the switch to 3:75 gears?

Hey guys,

I found a small leak point on the D44 while under the Z today. It's not a rapid leak, just enough to make the collar around the driver side yoke look a little wet with a light on it. So looks like I found a way to blow my tax return in a few months. The car is only a weekend driver toy so it's not a huge priority right now but curious to know what a set of 3:75 gears would do. Who has made the switch? I was already considering this but now I have more of a reason to go through with it.

I have heard of Ikerd's and I checked them out for the full rebuild kits and gear sets. So I have a place to source the parts but curious also if there's a builder who could be trusted to put it together and not have to worry about it howling.
1985 Corvette is offline  
Old 11-19-2018, 07:36 PM
  #2  
FASTAZU
CF Senior Member
 
FASTAZU's Avatar
 
Member Since: Feb 2002
Location: GA. Lost on 285.. just keeps going around!
Posts: 10,162
Thanked 283 Times in 258 Posts
2018 C4 of Year Finalist
2015 C4 of the Year Finalist
St. Jude Donor '16
Default

Most will say go with 4:10s but I went with 3:73 and they work great for my diving style. Had Marc do them when the car was at his place for the 500hp package.
FASTAZU is offline  
Old 11-19-2018, 08:57 PM
  #3  
ccmano
CF Senior Member
 
ccmano's Avatar
 
Member Since: Aug 2005
Location: Sparks NV
Posts: 1,346
Thanked 39 Times in 38 Posts
Default

Haibeck swears by the 4:10’s, http://www.zr1specialist.com/HAT%20W...ucts/gears.htm
I had them in my last car and plan to up grade the current one as well. It made a huge impact on day to day drivability. The car felt much more responsive and 6th gear was now usable. I’m sure the 3.73’s will help but check out 4.10’s before you make a final decision.
H

Last edited by ccmano; 11-19-2018 at 10:41 PM.
ccmano is offline  
Old 11-19-2018, 09:55 PM
  #4  
1985 Corvette
CF Senior Member
Thread Starter
 
1985 Corvette's Avatar
 
Member Since: May 2004
Location: Jacksonville Florida
Posts: 4,261
Thanks: 0
Thanked 50 Times in 38 Posts
Default

Originally Posted by FASTAZU View Post
Most will say go with 4:10s but I went with 3:73 and they work great for my diving style. Had Marc do them when the car was at his place for the 500hp package.
3:73 is what I meant, I think I had the existing 3:45s on the brain making the title and OP. I found a rather extensive discussion on the 4:10s vs 3:73s over on the registry forum.

http://www.zr1.net/forum/showthread.php?t=22970

Most likely old reading for the OGs around here but I'm having fun with it.

1985 Corvette is offline  
Old 11-22-2018, 10:19 AM
  #5  
Rkreigh
CF Senior Member
 
Member Since: Dec 1999
Location: Alexandria, Virginia, USA VA
Posts: 7,810
Thanked 74 Times in 67 Posts
Default

Originally Posted by 1985 Corvette View Post
3:73 is what I meant, I think I had the existing 3:45s on the brain making the title and OP. I found a rather extensive discussion on the 4:10s vs 3:73s over on the registry forum.

http://www.zr1.net/forum/showthread.php?t=22970

Most likely old reading for the OGs around here but I'm having fun with it.
the 4.10s work better in most situations. Once you start climbing over 600 at the tire a taller gear is needed to get much hope of any traction

I just went with 4.10s and bigger front and rear 18 tires make sure you stay within .75 front to rear diameters or you'll throw a traction control code

Phil got around this by machining a custom reluctor gear to run 345 tires in back which were probably 1 inch or so bigger than the fronts

enough to make the system unhappy
Rkreigh is offline  
Old 11-22-2018, 01:35 PM
  #6  
ZR1Bob
CF Senior Member
 
ZR1Bob's Avatar
 
Member Since: Apr 2007
Location: Lake Bluff IL
Posts: 830
Thanked 148 Times in 104 Posts
Default

I agree with most--I went with 4.10s and they seemed perfect. Hard to see why Chevrolet did not make them optional like they used to do in the old days but I am sure it was emissions related. Did them on the '93 fairly soon after purchase and they were the first thing I did with the '95 along with a Corsa exhaust and a short shifter. Really improved around town driving and the only racing issue is that you need to shift into fourth at the drag strip. I thought about the 3.73s and researched it a bit but concluded 4.10s would be best. --Bob
ZR1Bob is offline  
Old 11-23-2018, 12:09 PM
  #7  
Paul Workman
CF Senior Member
 
Paul Workman's Avatar
 
Member Since: Oct 2004
Location: "Below I-80" Illinois
Posts: 5,528
Thanked 200 Times in 186 Posts
Default

Originally Posted by ZR1Bob View Post
I agree with most--I went with 4.10s and they seemed perfect. Hard to see why Chevrolet did not make them optional like they used to do in the old days but I am sure it was emissions related. Did them on the '93 fairly soon after purchase and they were the first thing I did with the '95 along with a Corsa exhaust and a short shifter. Really improved around town driving and the only racing issue is that you need to shift into fourth at the drag strip. I thought about the 3.73s and researched it a bit but concluded 4.10s would be best. --Bob
Yeah, with similar motor setups, the difference between 4.10s (yours) and my 3.45s in the 1/2-mile WANNAGOFAST side-by-side saw you cross the finish line first, but at 138 mph in 5th gear vs. 144.2x with my 3.45s still in 4th. Somewhere shortly past the 1/2 mile point the 3.45s would be favored, I recon - not that it matters so much to me. (Considering Pete's 391 package tho, and 3.45s might keep first gear relevant.)
Paul Workman is offline  
Old 11-24-2018, 01:51 PM
  #8  
5abivt
CF Senior Member
 
5abivt's Avatar
 
Member Since: May 2002
Location: Toronto ontario
Posts: 4,638
Thanked 58 Times in 49 Posts
Default

I Like 3.73s I think its perfect. I took out the 4.09s in my Lt1 car for 3.73s with 480rwhp and 8k rpm limiter the 3.73s were perfect and allowed 1st gear to be useful with an actual street tire that I could go high speeds and corner with too. 4.09s even with bolt ons on an LT1 got real tiring real fast. with the 388 stroker it was a joke. I don't like the ratios in the zf its like a 4 speed to me. I hate that 5th is pretty much an overdrive so I prefer stock gears. topping out 4th is fast enough and I can use 5th for top speed which isn't often. Plus longer gearing = less shifts at speed so for how I like to drive I prefer to shift less among other reasons
5abivt is offline  
Old 11-24-2018, 10:49 PM
  #9  
Dominic Sorresso
CF Senior Member
 
Dominic Sorresso's Avatar
 
Member Since: Sep 2000
Location: Bartlett IL
Posts: 5,090
Thanked 114 Times in 92 Posts
Default

With 19s on the back, I needed to go to 4.10s just to be close to matching the overall ratio of stock wheels and 3.45s. It makes 6th more usable w 80mph putting the motor at about 1900rpm.

Last edited by Dominic Sorresso; 11-24-2018 at 10:50 PM.
Dominic Sorresso is offline  
Old 11-25-2018, 12:57 AM
  #10  
-=Jeff=-
CF Senior Member
 
-=Jeff=-'s Avatar
 
Member Since: Mar 1999
Location: Bartlett Illinois
Posts: 11,957
Thanked 96 Times in 92 Posts
Default

I love the fun I have around town with the 4.10s. But my car is mostly stock
-=Jeff=- is offline  
Old 11-28-2018, 02:19 AM
  #11  
Faster5
CF Senior Member
 
Member Since: Oct 2018
Location: Bellingham, wa.
Posts: 153
Thanked 4 Times in 4 Posts
Default

If you go with 373 it will cut a whole second of your 1/4 et best bang for your buck. I have a pumpkin with 273s I will sellfor $500 or use for the 1000 core they charge here at Wcc and get a new set of 411s��
Faster5 is offline  
Old 11-28-2018, 09:15 PM
  #12  
ZWILDZR1
CF Senior Member
 
ZWILDZR1's Avatar
 
Member Since: Aug 2018
Posts: 188
Thanks: 0
Thanked 14 Times in 13 Posts
Default

My first car was a 91 with Watson small primary tube headers, no cats, and a 3" early B&B exhaust, and a custom chip. It had the 4.10's and it ran great. I didn't have anything to compare it to as I hadn't driven a car with the 3.45's. At Bowling Green one year I was on the highway heading to the barbeque when I got into a little friendly competition with a stock geared car. I remember that we were dead even up to about 100 when I just started walking away until I let off around 150. My current car is 525 h.p. that Marc did and I think it will be better with a set of 4.10's.
ZWILDZR1 is offline  
Old 12-04-2018, 09:43 AM
  #13  
cuisinartvette
CF Senior Member
 
Member Since: Oct 2004
Location: Valencia Ca.
Posts: 67,555
Thanked 1,075 Times in 987 Posts
St. Jude Donor '05
Default

3.73 isnt really enough that youll feel it or feel good about the money spent. 4.10 isnt as steep a gear as it sounds its just right.
Went from 3.08 on another car to 3.73 and regretted it...week later did the 4.10 and all was right.
If you got a car that redlines say under 6k then 4.10 isnt always best
cuisinartvette is online now  
Old 12-12-2018, 12:23 PM
  #14  
Paul Workman
CF Senior Member
 
Paul Workman's Avatar
 
Member Since: Oct 2004
Location: "Below I-80" Illinois
Posts: 5,528
Thanked 200 Times in 186 Posts
Default

I'm still undecided. Switching back and forth between my 3.45 510chp and Ami's* 4.10s ~ 510 hp...its a LOT OF GEAR ROWING, especially in the mountain type twisty roads. It is great to run "The Dragon" in 2nd gear and let the rpm range of the LT5 handle the curves w/o having to row the gears (so much).

Of course, I'd like to have more torque throughout the rpm range. So, I guess its the old conundrum between gears and HP mods. 'The jury is still out'.

*Pete's cams, but smaller porting. Would be interesting to put it on a dyno someday out of curiosity.
Paul Workman is offline  
Old 12-12-2018, 01:24 PM
  #15  
Dominic Sorresso
CF Senior Member
 
Dominic Sorresso's Avatar
 
Member Since: Sep 2000
Location: Bartlett IL
Posts: 5,090
Thanked 114 Times in 92 Posts
Default

Originally Posted by Paul Workman View Post
I'm still undecided. Switching back and forth between my 3.45 510chp and Ami's* 4.10s ~ 510 hp...its a LOT OF GEAR ROWING, especially in the mountain type twisty roads. It is great to run "The Dragon" in 2nd gear and let the rpm range of the LT5 handle the curves w/o having to row the gears (so much).

Of course, I'd like to have more torque throughout the rpm range. So, I guess its the old conundrum between gears and HP mods. 'The jury is still out'.

*Pete's cams, but smaller porting. Would be interesting to put it on a dyno someday out of curiosity.
Put 19"s on the back, then the 4.10s will work fine.
Dominic Sorresso is offline  
Old 12-12-2018, 02:21 PM
  #16  
-=Jeff=-
CF Senior Member
 
-=Jeff=-'s Avatar
 
Member Since: Mar 1999
Location: Bartlett Illinois
Posts: 11,957
Thanked 96 Times in 92 Posts
Default

How about a 391 in your car, leave the gears alone?

lol
-=Jeff=- is offline  
Old 12-12-2018, 06:48 PM
  #17  
Paul Workman
CF Senior Member
 
Paul Workman's Avatar
 
Member Since: Oct 2004
Location: "Below I-80" Illinois
Posts: 5,528
Thanked 200 Times in 186 Posts
Default

Originally Posted by -=Jeff=- View Post
How about a 391 in your car, leave the gears alone?

lol
Oh, SUCHA novel idea! (NOT!)
Paul Workman is offline  
Old 12-12-2018, 07:17 PM
  #18  
-=Jeff=-
CF Senior Member
 
-=Jeff=-'s Avatar
 
Member Since: Mar 1999
Location: Bartlett Illinois
Posts: 11,957
Thanked 96 Times in 92 Posts
Default

Originally Posted by Paul Workman View Post
Oh, SUCHA novel idea! (NOT!)
lol..

too bad bad there isnít a PPP(Peteís Payment Plan) for a PPP (Peteís Performance Package)

not sure that that would fit under the tree as a Christmas gift either 😀
-=Jeff=- is offline  
Old 12-12-2018, 07:32 PM
  #19  
Dominic Sorresso
CF Senior Member
 
Dominic Sorresso's Avatar
 
Member Since: Sep 2000
Location: Bartlett IL
Posts: 5,090
Thanked 114 Times in 92 Posts
Default

Originally Posted by -=Jeff=- View Post

lol..

too bad bad there isnít a PPP(Peteís Payment Plan) for a PPP (Peteís Performance Package)

not sure that that would fit under the tree as a Christmas gift either 😀
excellent suggestion Jeff.
Dominic Sorresso is offline  
Old 12-27-2018, 10:49 PM
  #20  
Rkreigh
CF Senior Member
 
Member Since: Dec 1999
Location: Alexandria, Virginia, USA VA
Posts: 7,810
Thanked 74 Times in 67 Posts
Default

LT5 layaway plan. Participating member.
Rkreigh is offline  

Thread Tools
Search this Thread
Quick Reply: Who has made the switch to 3:75 gears?


Sponsored Ads
Vendor Directory

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: