Rear End Gear Ratio Change - ZR-1 Net Registry Forums

Josh · 02-01-2014

First post as a ZR-1 owner.

Recently purchased 1990 ZR-1 #2875 with 13,000 miles, all stock. Awesome car and a big step up in performance from my 93 LT1.

Initially I had a slight misfire at idle. Ohm'd injectors. 3 bad primaries. Replaced all 16 with new Delphi stainless injectors from FIC using Jerry's gaskets and o-rings (great products!). No more misfires.

I plan to eventually do the following upgrades to the car in this order:
-4.10 gears
-Long tube headers/exhaust (delete cats)
-Ported plenum/IH (and heads if I ever pull the engine).
-Updated PROM

So onto the first item, 4.10 gears.

The car pulls like crazy when RPM's are 4k-7k, but it feels a bit sluggish down low and the ratios are too tall in all gears for my tastes. That said, and considering future modifications, I have decided to go with 4.10:1.

Which brand, where to get, what additional parts needed, things to do while I'm in there, tips and tricks, etc.

Thanks

We Gone · 02-01-2014

Welcome & Congrats, you came to the right place. 4.10s are one of the most popular upgrades good bang for the $. I'm sure someone will post up for you a good builder in your area. I think it is Cory Henderson?

WVZR-1 · 02-01-2014

Quote:

Originally Posted by Josh

So onto the first item, 4.10 gears.

The car pulls like crazy when RPM's are 4k-7k, but it feels a bit sluggish down low and the ratios are too tall in all gears for my tastes. That said, and considering future modifications, I have decided to go with 4.10:1.

Which brand, where to get, what additional parts needed, things to do while I'm in there, tips and tricks, etc.

Thanks

I'll leave the gear "branding" alone but if you're doing the 4.10 ratio "for sure" you need Marc's speedometer correction gear set. You might as well do those "NOW" so that they're in hand. Regardless of "branding" I believe I'd make sure I bought a gear set that included a 226mm ring gear vs. the 216mm stock. You may have to massage the housing or the cover OR maybe both but it would I believe the preferred.

Speedometer stuff:

http://www.zr1specialist.com/HAT%20W...on%20Gears.htm

alnukem · 02-01-2014

Sounds like a good, logical plan.

Jagdpanzer · 02-01-2014

Welcome to the brotherhood.
Several of us run the lager diameter ring gear Dana Spicer 4.10 gear set designed for the Dodge Viper which also uses the Dana 44 rear end. It's available from your local Mopar parts source under PN P5007043.

ghlkal · 02-01-2014

Quote:

Originally Posted by Josh

Recently purchased 1990 ZR-1 #2875 with 13,000 miles, all stock. Awesome car and a big step up in performance from my 93 LT1.

Congrats and welcome

Are you planning on doing the work yourself?

You're three hours from Henderson's shop in New Braunfels. If you haven't investigated Corey's services, you should.

Blue Flame Restorations · 02-01-2014

Welcome, Josh! Congrats on the new Z!

I have 4:10's in one of my Z's and love them. Great choice, IMO.

Let the fun begin!!!

LGAFF · 02-01-2014

I would do a port and tune first

bradley · 02-02-2014

defiantly go see corey he did the same thing to my 90 as you want to do to yours . my car went from 331 rwhp to 409.9 wrhp . makes the car way fun to drive .

Josh · 02-02-2014

Thanks ya'll. Yes I will install them myself, that's half the fun!

My list so far:
-Mopar Viper 4.10 gear set PN P5007043
-Haibeck 4.10 Speedo gears
-Amsoil SEVERE GEAR 75W-90 Synthetic EP Lubricant (2 qts)
-Amsoil Slip lock additive
-Pinion & Axle yoke seals
-RTV silicone
-Pinion shims

What am I missing?

I was not planning to replace bearings, u-joints, etc. as everything works properly now and the car only has 13,000 miles, but I will inspect everything while it's apart of course.

Corey's site is down right now, but I hear he makes some nice headers, so I'll definitely be considering him for those.

02-01-2014	#1
Josh Join Date: Oct 2013 Location: Magnolia, TX Posts: 10	Rear End Gear Ratio Change First post as a ZR-1 owner. Recently purchased 1990 ZR-1 #2875 with 13,000 miles, all stock. Awesome car and a big step up in performance from my 93 LT1. Initially I had a slight misfire at idle. Ohm'd injectors. 3 bad primaries. Replaced all 16 with new Delphi stainless injectors from FIC using Jerry's gaskets and o-rings (great products!). No more misfires. I plan to eventually do the following upgrades to the car in this order: -4.10 gears -Long tube headers/exhaust (delete cats) -Ported plenum/IH (and heads if I ever pull the engine). -Updated PROM So onto the first item, 4.10 gears. The car pulls like crazy when RPM's are 4k-7k, but it feels a bit sluggish down low and the ratios are too tall in all gears for my tastes. That said, and considering future modifications, I have decided to go with 4.10:1. Which brand, where to get, what additional parts needed, things to do while I'm in there, tips and tricks, etc. Thanks

02-01-2014	#4
alnukem Join Date: Jan 2010 Location: Freedom, PA Posts: 275	Re: Rear End Gear Ratio Change Sounds like a good, logical plan.

02-01-2014	#5
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,649	Re: Rear End Gear Ratio Change Welcome to the brotherhood. Several of us run the lager diameter ring gear Dana Spicer 4.10 gear set designed for the Dodge Viper which also uses the Dana 44 rear end. It's available from your local Mopar parts source under PN P5007043. __________________ Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake

02-01-2014	#7
Blue Flame Restorations Join Date: Feb 2010 Location: Pendleton, IN Posts: 3,899	Re: Rear End Gear Ratio Change Welcome, Josh! Congrats on the new Z! I have 4:10's in one of my Z's and love them. Great choice, IMO. Let the fun begin!!! __________________ 1988 KOH Prototype EX5023 sold 1990 ZR-1 #444 Convertible 1990 ZR-1 Black #966 1991 ZR-1 Quazar Blue #296 1957 Duntov SS Project

02-01-2014	#8
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,180	Re: Rear End Gear Ratio Change I would do a port and tune first __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

02-01-2014	#2
We Gone Join Date: Apr 2004 Location: Atlanta, GA Posts: 2,170	Re: Rear End Gear Ratio Change Welcome & Congrats, you came to the right place. 4.10s are one of the most popular upgrades good bang for the $. I'm sure someone will post up for you a good builder in your area. I think it is Cory Henderson? __________________ Steve 1990 Steel Blue/Black #2355 1990 Red/Red #1473 1991 Quasar /Black #118 Sold 1991 Turquoise/Black #766 Parted Out 1993 Yellow/White #179 Sold 1990 Black/Gray #1361 Headers/4:10s Sold

02-02-2014	#9
bradley Join Date: Aug 2013 Location: ridgecrest ca Posts: 103	Re: Rear End Gear Ratio Change defiantly go see corey he did the same thing to my 90 as you want to do to yours . my car went from 331 rwhp to 409.9 wrhp . makes the car way fun to drive .

02-02-2014	#10
Josh Join Date: Oct 2013 Location: Magnolia, TX Posts: 10	Re: Rear End Gear Ratio Change Thanks ya'll. Yes I will install them myself, that's half the fun! My list so far: -Mopar Viper 4.10 gear set PN P5007043 -Haibeck 4.10 Speedo gears -Amsoil SEVERE GEAR 75W-90 Synthetic EP Lubricant (2 qts) -Amsoil Slip lock additive -Pinion & Axle yoke seals -RTV silicone -Pinion shims What am I missing? I was not planning to replace bearings, u-joints, etc. as everything works properly now and the car only has 13,000 miles, but I will inspect everything while it's apart of course. Corey's site is down right now, but I hear he makes some nice headers, so I'll definitely be considering him for those.