Tranny(not that kind) and Rear - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jparks · 01-05-2011, 02:30 PM

Been thinking for a while, as I'm soon to have a roller, that I want to change my transmission and rear end gears. I'm looking for opinions as to what a good setup will be. I've got a 383 built with around 500hp/500tq, actual specs are on my signature. I want this to be highway friendly but I also want it to get on it out of the hole. In my mind I'm thinking 700r4 with an eaton posi and 3.73 gears out back. Something in the back of my mind keeps telling me I need to go with a different gear though, maybe 4.10. This truck will be 75 street but will be driven often 90 miles away to Houston and 250 miles away to Austin so I want it to be decent on the highway as well. What do you guys think?

haysonj · 01-05-2011, 03:13 PM

I've got a 383 T400 GV OD with 4:10 gears and 35 in tires truck has plenty of low end torque and cruises 65 around 2200 rpm so I get decent mileage.

Jparks · 01-05-2011, 03:57 PM

Guess I should have mentioned I'm running a 29" tire, not sure how much that comes into play, the th400 with OD at that speed and rpm sounds good if that would work with my tire size
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Jacfourteen · 01-05-2011, 05:03 PM

I have a 3.73 and a 4l60e in my 01 tahoe with 32" tires and it is good all around, good get up and spins about 2000 rpm @ 70 mph. With your smaller tires it will have a bit more lowend and RPM at cruise. I think 4.10 is a little too deep for your plans.

sickred72 · 01-05-2011, 09:25 PM

i have a 383 (559whp) in mine with a 700r4 trans with 4th gear lockup only. 308 posi. th e 700's have a low 1st gear and you will be able to use the overdrive on the freeway. 22" wheels on mine. and its gets about 14mpg. i have a true 3200 stall converter ( 10" ) im in the transmission business ( torque converter mfg )
it seems to be a nice setup...jerald

treveiger · 01-05-2011, 11:12 PM

I would stick with 3.73s, that thing is pulling enough power to light up the tires without question with those gears. With that motor you arent going to be getting the best gas mileage and with the 4.10s itd just be a lot worse.

01-05-2011, 02:30 PM	#1
Jparks Registered User Join Date: Aug 2010 Location: Nederland, TX Posts: 429	Tranny(not that kind) and Rear Been thinking for a while, as I'm soon to have a roller, that I want to change my transmission and rear end gears. I'm looking for opinions as to what a good setup will be. I've got a 383 built with around 500hp/500tq, actual specs are on my signature. I want this to be highway friendly but I also want it to get on it out of the hole. In my mind I'm thinking 700r4 with an eaton posi and 3.73 gears out back. Something in the back of my mind keeps telling me I need to go with a different gear though, maybe 4.10. This truck will be 75 street but will be driven often 90 miles away to Houston and 250 miles away to Austin so I want it to be decent on the highway as well. What do you guys think? __________________ 72 SWB - Porterbuilt Front/Rear, 22's, 496bbc - "Outkast" 68 Stepside - Porterbuilt Coilover Chassis, 22's, LS3 - "Badfinger"

01-05-2011, 03:13 PM	#2
haysonj Registered User Join Date: Dec 2007 Location: Santa Maria, Ca. Posts: 1,423	Re: Tranny(not that kind) and Rear I've got a 383 T400 GV OD with 4:10 gears and 35 in tires truck has plenty of low end torque and cruises 65 around 2200 rpm so I get decent mileage. __________________ 69 Chevy 4x4 383 Power

01-05-2011, 03:57 PM	#3
Jparks Registered User Join Date: Aug 2010 Location: Nederland, TX Posts: 429	Re: Tranny(not that kind) and Rear Guess I should have mentioned I'm running a 29" tire, not sure how much that comes into play, the th400 with OD at that speed and rpm sounds good if that would work with my tire size Posted via Mobile Device __________________ 72 SWB - Porterbuilt Front/Rear, 22's, 496bbc - "Outkast" 68 Stepside - Porterbuilt Coilover Chassis, 22's, LS3 - "Badfinger"

01-05-2011, 05:03 PM	#4
Jacfourteen Big Red - Now its a SWB! Join Date: Jun 2009 Location: Oroville, Ca Posts: 1,624	Re: Tranny(not that kind) and Rear I have a 3.73 and a 4l60e in my 01 tahoe with 32" tires and it is good all around, good get up and spins about 2000 rpm @ 70 mph. With your smaller tires it will have a bit more lowend and RPM at cruise. I think 4.10 is a little too deep for your plans. __________________ 68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread 41 3/4 ton (wife's)-flatbed, fully restored to original 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's

01-05-2011, 09:25 PM	#5
sickred72 Registered User Join Date: Oct 2005 Location: oregon Posts: 204	Re: Tranny(not that kind) and Rear i have a 383 (559whp) in mine with a 700r4 trans with 4th gear lockup only. 308 posi. th e 700's have a low 1st gear and you will be able to use the overdrive on the freeway. 22" wheels on mine. and its gets about 14mpg. i have a true 3200 stall converter ( 10" ) im in the transmission business ( torque converter mfg ) it seems to be a nice setup...jerald Attached Images Last edited by sickred72; 01-05-2011 at 09:26 PM.

01-05-2011, 11:12 PM	#6
treveiger Senior Member Join Date: Jul 2010 Location: South Dakota Posts: 4,093	Re: Tranny(not that kind) and Rear I would stick with 3.73s, that thing is pulling enough power to light up the tires without question with those gears. With that motor you arent going to be getting the best gas mileage and with the 4.10s itd just be a lot worse. __________________ 1969 Chevy c20(Miss Hackjob)



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