Rear end gear info needed: - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*Zkast* · 10-18-2002, 12:01 AM

I'm looking for first hand experiences from people that have "had" a 3:08 gear ratio and switched to 4:11's.
I'm a little disappointed in my new engine setup and im sure these 308's are killing the engine's HP/Torque.... I just haven't had the time or money to change them out yet. I fully understand the drawbacks to running the 4:11's, thats not what im asking for lol. I'm after performance and that alone. Screw gas mileage, screw highway driving

For those that have done this change, what kind of "WOW" factor are we talking about?

Funny, I've been in the automotve repair biz for 12 years but havent had the chance to swap up or down gear sizes... Just repair whats there. So I haven't felt this change first hand.

flyin99 · 10-18-2002, 12:24 AM

Well, this probably won't help a whole lot, but I went from 3.08 to 4.56 in mine and it was absolutely AWESOME!!!!!!....highway driving sucked, as well as mileage, but it was a Mustang buster with that gear in it..now I must say that it also had a "lincoln lock" differential, that was probably one of the more dangerous things I have done, but it was VERY VERY quick...............just my 2 or 3 cents worth

oh yeah, the engine was a 355.....10.25 to 1..........041 heads...........294-.525 solid lift cam......Holley 750 DBl pumper.Victor Jr. and headers..........

*Zkast* · 10-18-2002, 12:27 AM

Did you have the 308's after your engine swap? If so, what was your thoughts on the engine performance with 308 gears.

I need to stop d*ckin around and put the gears in lol, but I have too many things including Christmas time to deal with right now.

flyin99 · 10-18-2002, 12:31 AM

Yes, I ran both gears in mine after the engine swap...............it did nothing, but sound fast with the 3.08's...........if you took somebody for a ride with 3.08's, it would definately change the way they looked at BIG cams and street driving.........

It would have to have a low gear to run like it was meant to.hope this helps ya........

*Zkast* · 10-18-2002, 12:34 AM

Heck ya it helps

Now I know im not just thinking the ole truck will never "get it". It's fast don't get me wrong, but its not what I expected with this much engine. Man I catch myself looking for red lights so I can stop and listen to the idle LMAO. But if I want to feel the "set me back into the seat" feeling, I have do a rolling start (15ft or so) and even then its lacking.

crazy longhorn · 10-18-2002, 12:36 AM

The biggest jump i made was from a 3.07 to a 3.73,& the old 327 loved the gear! I went from a 3.40 to a 4.10 in the longhorn(12 bolt rear), & i like the gear, but have to say for any hyway driving the 3.73s are a better all around gear. Milage......whats that!

flyin99 · 10-18-2002, 12:42 AM

I tried them too...........3.73's that is..................ummmmmmm.......it ran OK with these gears, but the 4.56, ofcourse just brought it to life..........it would spin 7,500 rpm quickly, if ya didn't watch it.......but the welded spider gears, I will never do again

Adam12 · 10-18-2002, 01:14 AM

I have the 3.08's also just wonderin what id be lookin to pay for posi 3.73 or 4.11 new or used.

70c10 · 10-18-2002, 07:52 AM

Adam12,
I'm about to purchase an Eaton Posi frpm Tomsdifferentials.com for $280. That's the best price I have seen so far.

Adam12 · 10-19-2002, 12:48 AM

thanks

dion · 10-19-2002, 02:57 PM

What do you guys think would be better for my truck, 4:10 or 3:73? Check my sig.

*Zkast* · 10-19-2002, 03:02 PM

In your case, the bigger the gear the better. You've got alot of HP making goodies there... but they are also killing the torque on low end.

Victor Jr, high duration, 3000 stall do nothing for low end performance so you need to free up the engine a bit (using 4:11's) and not lug it down. IMHO

10-18-2002, 12:01 AM	#1
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	Rear end gear info needed: I'm looking for first hand experiences from people that have "had" a 3:08 gear ratio and switched to 4:11's. I'm a little disappointed in my new engine setup and im sure these 308's are killing the engine's HP/Torque.... I just haven't had the time or money to change them out yet. I fully understand the drawbacks to running the 4:11's, thats not what im asking for lol. I'm after performance and that alone. Screw gas mileage, screw highway driving For those that have done this change, what kind of "WOW" factor are we talking about? Funny, I've been in the automotve repair biz for 12 years but havent had the chance to swap up or down gear sizes... Just repair whats there. So I haven't felt this change first hand.

10-18-2002, 07:52 AM	#9
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	Adam12, I'm about to purchase an Eaton Posi frpm Tomsdifferentials.com for $280. That's the best price I have seen so far. __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

10-19-2002, 02:57 PM	#11
dion 72 Cheyenne Join Date: Oct 2001 Location: San Diego Posts: 2,086	What do you guys think would be better for my truck, 4:10 or 3:73? Check my sig. __________________ Burnout Idle 1972Cheyenne 1966/67Stouts

10-18-2002, 12:24 AM	#2
flyin99 creator of kong Join Date: Mar 2001 Location: Kentucky Posts: 538	Well, this probably won't help a whole lot, but I went from 3.08 to 4.56 in mine and it was absolutely AWESOME!!!!!!....highway driving sucked, as well as mileage, but it was a Mustang buster with that gear in it..now I must say that it also had a "lincoln lock" differential, that was probably one of the more dangerous things I have done, but it was VERY VERY quick...............just my 2 or 3 cents worth oh yeah, the engine was a 355.....10.25 to 1..........041 heads...........294-.525 solid lift cam......Holley 750 DBl pumper.Victor Jr. and headers..........

10-18-2002, 12:27 AM	#3
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	Did you have the 308's after your engine swap? If so, what was your thoughts on the engine performance with 308 gears. I need to stop d*ckin around and put the gears in lol, but I have too many things including Christmas time to deal with right now.

10-18-2002, 12:31 AM	#4
flyin99 creator of kong Join Date: Mar 2001 Location: Kentucky Posts: 538	Yes, I ran both gears in mine after the engine swap...............it did nothing, but sound fast with the 3.08's...........if you took somebody for a ride with 3.08's, it would definately change the way they looked at BIG cams and street driving......... It would have to have a low gear to run like it was meant to.hope this helps ya........

10-18-2002, 12:34 AM	#5
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	Heck ya it helps Now I know im not just thinking the ole truck will never "get it". It's fast don't get me wrong, but its not what I expected with this much engine. Man I catch myself looking for red lights so I can stop and listen to the idle LMAO. But if I want to feel the "set me back into the seat" feeling, I have do a rolling start (15ft or so) and even then its lacking.

10-18-2002, 12:36 AM	#6
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	The biggest jump i made was from a 3.07 to a 3.73,& the old 327 loved the gear! I went from a 3.40 to a 4.10 in the longhorn(12 bolt rear), & i like the gear, but have to say for any hyway driving the 3.73s are a better all around gear. Milage......whats that!

10-18-2002, 12:42 AM	#7
flyin99 creator of kong Join Date: Mar 2001 Location: Kentucky Posts: 538	I tried them too...........3.73's that is..................ummmmmmm.......it ran OK with these gears, but the 4.56, ofcourse just brought it to life..........it would spin 7,500 rpm quickly, if ya didn't watch it.......but the welded spider gears, I will never do again

10-18-2002, 01:14 AM	#8
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	I have the 3.08's also just wonderin what id be lookin to pay for posi 3.73 or 4.11 new or used.

10-19-2002, 12:48 AM	#10
Adam12 I hate trannys Join Date: Dec 2001 Location: Bakersfield,CA Posts: 160	thanks

10-19-2002, 03:02 PM	#12
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	In your case, the bigger the gear the better. You've got alot of HP making goodies there... but they are also killing the torque on low end. Victor Jr, high duration, 3000 stall do nothing for low end performance so you need to free up the engine a bit (using 4:11's) and not lug it down. IMHO



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