Wow, 4.10 rear end? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jorgensensc · 04-02-2004, 02:49 PM

I finally got around to checking my rearend gears using an internet calculator.
Looks like I got 4.10s in the rear.

I run 3300 RPMs at 60 Mph.
I run 275/60r15 (28 inch tire)

Does this sound about right to anyone else?

I need better MPG's andwas thinking of running an overdrive tranny.
Should I keep these gears and get an overdrive, or just get different gears?

Anybody want to trade rear ends?? Mine is a coil spring rear?

Longhorn Man · 04-02-2004, 02:52 PM

if your truck is fairly origial, that would be listed on the glove box door.

dinnut · 04-02-2004, 02:53 PM

id leave the gears and get an overdrive. that would be a great addition... but a gear change will be a lot cheaper!

Lobo'74 · 04-02-2004, 04:54 PM

Truck runs 2650 rpm at 60 mph running 31" tires.
Truck runs 3000 rpm at 66.5 mph, same 31" tires.

What equations do I use to figure out the rear end? I think its a 4:11, but I'm not positive. It is the stock 1967 I6 rear end that came on Truck originally.

**CPNE** · 04-02-2004, 05:00 PM

Quote:

Originally posted by Lobo'74
Truck runs 2650 rpm at 60 mph running 31" tires.
Truck runs 3000 rpm at 66.5 mph, same 31" tires.

What equations do I use to figure out the rear end? I think its a 4:11, but I'm not positive. It is the stock 1967 I6 rear end that came on Truck originally.

c10 = 3:73 stock I6 manual, 4:11 optional
c20 = 4:56 stock I6 manual, 4:11 optional

Lobo'74 · 04-02-2004, 05:04 PM

Thanks CPNE. I also did a web search and found a calculator while you were posting. Came back to the site and you had answered the question for me.

Thanks

70-Chevy · 04-02-2004, 05:30 PM

what size rear end is it?
what lug?

i had a 6 lug, 12 bolt that i would like to have 4.10 in. let me know.
chris

LooseCannon · 04-02-2004, 05:36 PM

One way to be 100% accurate... remove the rear end cover and divide the number of teeth on the ring gear by the number of teeth on the pinion. It’s probably about time to change the 90 weight anyway!

Longhorn Man · 04-02-2004, 06:21 PM

Loose Cannon...that's my line! (I normally answer with that for the past 3 years)
I'll add that avter 10 years, the oil is not doing all it should be doing. (acording to our indipendent oil lab we use at the shop)

jorgensensc · 04-02-2004, 09:08 PM

I will probably take the cover off, but I just replaced all the fluid about 8 months ago. I stupidly didn't check then. This truck was an original 350, so I suppose the rear end was changed at some point. They didn't orginally come with 4.10 or 4.11 did they?
As for the glove box, the po removed the sticker and painted over the area when the truck was repainted.

450hp,
Mine is a 12 bolt 5 lug rear. I think shipping would probably be a little high from here to there though.

cdowns · 04-02-2004, 09:26 PM

the computer game things are a fine tool but it makes the assumption that your speedometer is accurate

my new 72 · 04-02-2004, 09:49 PM

I've got a 3.07 coil in mine I would like to trade.

jorgensensc · 04-02-2004, 09:50 PM

I have driven by those speed trap things and my speedo is darn near on the money. My tach is also right on. T 40 mph on theres I showed 41mph.

RON WOODGEARD · 04-03-2004, 03:35 AM

http://www.summitracing.com/landing/...converter2.htm

04-02-2004, 02:49 PM	#1
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	Wow, 4.10 rear end? I finally got around to checking my rearend gears using an internet calculator. Looks like I got 4.10s in the rear. I run 3300 RPMs at 60 Mph. I run 275/60r15 (28 inch tire) Does this sound about right to anyone else? I need better MPG's andwas thinking of running an overdrive tranny. Should I keep these gears and get an overdrive, or just get different gears? Anybody want to trade rear ends?? Mine is a coil spring rear? __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

04-02-2004, 02:53 PM	#3
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	id leave the gears and get an overdrive. that would be a great addition... but a gear change will be a lot cheaper! __________________ 70 longbed 496/th400/Ford 9"

04-02-2004, 04:54 PM	#4
Lobo'74 Registered User Join Date: Nov 2002 Location: Charlottesville, VA Posts: 404	I'm lookin' too. Truck runs 2650 rpm at 60 mph running 31" tires. Truck runs 3000 rpm at 66.5 mph, same 31" tires. What equations do I use to figure out the rear end? I think its a 4:11, but I'm not positive. It is the stock 1967 I6 rear end that came on Truck originally. __________________ "Truck" '67 small window '79 350 .030 over, LT1 "clone"

04-02-2004, 05:04 PM	#6
Lobo'74 Registered User Join Date: Nov 2002 Location: Charlottesville, VA Posts: 404	FAST response Thanks CPNE. I also did a web search and found a calculator while you were posting. Came back to the site and you had answered the question for me. Thanks __________________ "Truck" '67 small window '79 350 .030 over, LT1 "clone"

04-02-2004, 05:30 PM	#7
70-Chevy -Chris Join Date: Sep 2002 Location: Moyock, NC Posts: 622	im interested in swapping what size rear end is it? what lug? i had a 6 lug, 12 bolt that i would like to have 4.10 in. let me know. chris __________________ 1970 Chevy C-10 P/U, Shortbed, Fleetside - 5/7 drop, 496, TH400, 12 bolt. BUILD THREAD - http://67-72chevytrucks.com/vboard/s...d.php?t=404481 2012 F250 Super Duty P/U - intake, exhaust, tuner, 4" lift with 35's 2017 Chevy Suburban (Wifes Car) - Fully Loaded & Stock "Some people spend an entire lifetime wondering if they made a difference in the world. But, the Marines don't have that problem." Ronald Reagan, President of the United States; 1985

04-02-2004, 02:52 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	if your truck is fairly origial, that would be listed on the glove box door.

04-02-2004, 05:36 PM	#8
LooseCannon Registered User Join Date: Mar 2004 Location: Boiling Springs, PA Posts: 391	One way to be 100% accurate... remove the rear end cover and divide the number of teeth on the ring gear by the number of teeth on the pinion. It’s probably about time to change the 90 weight anyway! __________________ Bagged 05 Suburban Bagged Baby Blue 68

04-02-2004, 06:21 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Loose Cannon...that's my line! (I normally answer with that for the past 3 years) I'll add that avter 10 years, the oil is not doing all it should be doing. (acording to our indipendent oil lab we use at the shop)

04-02-2004, 09:08 PM	#10
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	I will probably take the cover off, but I just replaced all the fluid about 8 months ago. I stupidly didn't check then. This truck was an original 350, so I suppose the rear end was changed at some point. They didn't orginally come with 4.10 or 4.11 did they? As for the glove box, the po removed the sticker and painted over the area when the truck was repainted. 450hp, Mine is a 12 bolt 5 lug rear. I think shipping would probably be a little high from here to there though. __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

04-02-2004, 09:26 PM	#11
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	the computer game things are a fine tool but it makes the assumption that your speedometer is accurate __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

04-02-2004, 09:49 PM	#12
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	I've got a 3.07 coil in mine I would like to trade. __________________ I'm going to Law School, wanna debate? It's good practice.

04-02-2004, 09:50 PM	#13
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	I have driven by those speed trap things and my speedo is darn near on the money. My tach is also right on. T 40 mph on theres I showed 41mph. __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

04-03-2004, 03:35 AM	#14
RON WOODGEARD Resident Young Old Dude ! Join Date: Jul 2001 Location: Nevada Posts: 1,948	http://www.summitracing.com/landing/...converter2.htm

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