4:11 rear end ... Anyone?

[jondancer]

so, i'v got the chance to buy a complete rear end with axles with 4:11 gears and posi . i have a 350/350 turbo trans. would that rear end be not realistic for a cruiser? i want to be able to cruise around going faster than 60 mph and not have to worry about my rpms . anyone with a 2wd running 4:11 ' s?
thanks

[70cst]

Originally Posted by jondancer

so, i'v got the chance to buy a complete rear end with axles with 4:11 gears and posi . i have a 350/350 turbo trans. would that rear end be not realistic for a cruiser? i want to be able to cruise around going faster than 60 mph and not have to worry about my rpms . anyone with a 2wd running 4:11 ' s?
thanks

I'll take a guess and say 4:11 gears would be pushing it as a cruiser but I'll let others chime in

[CG]

You need to plug in rear gearing ... trans gearing ... and tire height. I know Ive seen someone post the formula before. I bet it turns up soon =)

[Ackattack]

I have 4:10s in my '68....but I have a 5.3L and 4L60E.....so its lots o' fun.

I wouldn't recommend it without OD

[ChevLoRay]

If you were to run those gears behind a 700R4, it wouldn't be too bad on the freeways.

But, you're gonna turn some revs if you run it without an overdrive gearbox. It'll pull some stumps on the git-go, tho.

[Longhorn Man]

You'll be reving too high for most people's taste. (this is assuming you have a street truck with normal sized tires, and not a 4X4 with bug mudder tires)
Most people on here complain about 4.10/4.11 gears and would give anything to drop there cruise RPMs (put me in that group)

[o6r1man]

I bet my dd has 4.11 or lower. It turns 36-3700 at 65 mph. I have had a lot of car/trucks with 3.73s and they seem to turn around 3k at 60-65 depending on the tire size. But I have a newer truck that I drive if I have to go on the hwy and I live in a small town so low gears are not hurting me, heck they may be helping my in town mpg. Dont have to give it as much thottle to get going.

[jondancer]

thanks guys

[70cst]

Great info ...

[68Stepbed]

I just switched from 3.73 gears to 3.07 gears in my 68. I have a 350/TH350 combo. I went from 3400 rpm at 70mph to about 2500 rpm at 70mph. I'm fixing to take a trip to Nashville in it next weekend. It'll be nice to cruise at freeway speeds instead of chuggin along at 55-60mph like I usually do.

[Bishop73]

I would gladly trade my 4.10's for some 3.73's, or replace my TH350 for a 700R4.

[cadillacart]

I have a set of 3.5x's ready to replace my 4.11's. 60Mph gets the revs too high for my taste right now.

[Classic69]

My '69 has 4.56 gears with a SBC 327 and a TH350 combo. It turns around 4000 RPM at 70 mph. Id love to switch em out for some 3.73 gears in the future. My truck is a cruiser, that I drive a couple times a week to have some fun with and take to shows, so its not like its a daily driver. But it is a screamer on the highway! lol

[chevytruckluver]

As stated above, if you change to an overdrive tranny you will be good, otherwise hope you are just cruising around in town. Gas mileage will suck or should I say the gas will be sucked from the tank rather quickly.

[Classic69]

Oh I know...but my issue was when I rebuilt the TH350 tranny, I wanted to swap it for a 700R4, but I had to replace my driveshaft cuz its a couple inches longer. So I opted out of doing that at the time and just stuck with it. I get about 12 mpg and I mostly just drive it around town, but I live out in the country (15-20 mins outside of town), so I do some highway driving.

Somewhere down the road, when my engine needs to be rebuilt or replaced, ill maybe swap for a 700R4 and fix my driveshaft. But for now, im ok with what I got, ill just maybe swap out my 4.56's for some 3.73's eventually...

I mean I have my 2.4L I-4 Chevy Cavalier Z24 as my daily driver...30 mpg

[fair1138]

Im was running 4.56, now I have 3.73 with a rear tire 29". At 55-60 mph, its about 2500 rpm. Im even running with a gear drive and I dont think its bad.

[gcburdic]

you could change out the gear and pinion down to 3.73....that posi carrier will accept it with no problems....

[eightbanger]

I'm a 4.11 user with a 400 & 454, and by the time i'm doing 50mph it's already starting to scream, I do tend to stay away from hwy driving because of the gearing, but it sure is fun on local streets pulling away from stop lights.

[Fitz]

Originally Posted by jondancer

so, i'v got the chance to buy a complete rear end with axles with 4:11 gears and posi . i have a 350/350 turbo trans. would that rear end be not realistic for a cruiser? i want to be able to cruise around going faster than 60 mph and not have to worry about my rpms . anyone with a 2wd running 4:11 ' s?
thanks

You didn't say what tire size you're running and it makes a difference. Assuming you're using a 275/60 R 15
and your TH350 is a stocker the ratio's are:
2.52 1st
1.52 2nd
1.0 3rd
coupled with a 4.11 rear

give final drive ratio's of:

10.56 1st
6.25 2nd
4.11 3rd

which means you're turning 3127 rpm at 60 mph and 3650 at 70. That's a bit high and your truck is going to be very noisy. Switching to a 3.73 drops the rpm at 60 mph to 2838...not much of an improvement.

A 3.07 rear drops you to 2330 RPM at 60 mph but your truck will run slower than a 20 year old Honda Civic with two broken sparkplugs.

When I built my truck I used a 4.10 rear gearset with a TH400 which would have given me the same rpm numbers as yours BUT I added a Gear Vendors 0.7 : 1 overdrive so when I want acceleration it's set to 1:1 and the revs at 70 mph are 3640 but when I want to cruise it's set at 0.7:1 and the 70 mph RPM is 2551. All the difference in the world which is why some of the guys on this board like 700R4's. They will also give you the same effect as using a 0.7 :1 overdrive.

[long69]

ratios are ratios so i'll relate this to my old 2000 tacoma. it had a 411 rear end with 31 inch tires (this was stock) in overdrive it would turn about 2200@70mph, in third (1:1) it would turn about 3000@70mph. so 411's with 31 inch tires are not that bad even without overdrive. i think the trick is to find the best rpm to get the best mpg. i do know that i would get 20 mpg in the tacoma all day long at 70mph but drop it to 55-60 and i could get 25mpg.

[72peace]

I'm running a 350/th350 with 4.11 posi and 235/70R15's which puts me at around 3200 @ 60mph. I'm having a guy rebuild a 200-4R (because it's a direct replacement for the th350) which will give me a .67 o/d and hopefully a little better mpg. I found this really cool calculator to determine what size rear will give you the rpms you want and at what speed. Just put in your target rpm and tire size and it shows your speed with different rear ends ratios. Here's the link: http://www.angelfire.com/fl/procrastination/rear.html

Cheers,

[montoya22]

i have a 69 with the og 4 speed trans (1 gear granny) and i have to say i love my 411's , even more so when a ricer wants to throw down. but its my daily driver and i twist at 3200-3400 on the tack when im rolling 60-70ish. im loooking into a few diffrent oppitions , >1. change to 3.73's<, >2.t5 tranny swap<, > 4 speed munci or 400 turbo<

[Already Gone]

Originally Posted by montoya22

i have a 69 with the og 4 speed trans (1 gear granny) and i have to say i love my 411's , even more so when a ricer wants to throw down. but its my daily driver and i twist at 3200-3400 on the tack when im rolling 60-70ish. im loooking into a few diffrent oppitions , >1. change to 3.73's<, >2.t5 tranny swap<, > 4 speed munci or 400 turbo<

Have you thought of a 6 speed Tremec ? you coukd keep your 4:11's and stil cruse at 2500 RPM at 70 MPH
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[70c10stepside]

Turbo 400 with 4.11 here. Haven't played around to much yet, so dont kill me if I get something wrong broke Speedo also. At 45-50 I'm turning about 2200. 65 I think is 3600 or so. Haven't been on a high way yet, with someone along side. Just been on the back roads with the new set up. I will be going 5 or 6 speed, though. Ive gotten (I think) 9-13 mpg with a really healthy 355
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[jocko]

I might have missed it, but what are you running now for rear end gearing? You mention you want to run around over 60 - so I'll assume that would happen fairly often and on the highway. If you change nothing else in your truck, I would definitely not go to a 4.11. It just sounds cool to say it, it is not as streetable as a 3.73, and certainly not as highway-able.

If you post your tire diameter (or size), we can provide exact numbers. But my personal opinion, since you specifically mentioned highway driving as a goal, is that the few extra puffs of smoke you may eek off the tires with a 4.11 at a stoplight is not at all worth what you lose in highway cruising ability. I'm not saying it can't be done, I'm saying it's better with a higher gear, that's all.

A much more streetable approach, that gives highway driving AND low end deeper gearing is an overdrive trans (o/d trans 1st gear ratios are normally a good bit deeper than TH400s and TH350s). May not be in the budget, but I'd save my $ before I sunk it in 4.11s. If you buy the 4.11s, then you'll need/want the o/d transmission just to make up for the rear end gearing on the highway and get back to where you were before you started.

For all those posting your rpms at a certain speed - are you reading that off the speedos after a gear swap or with the non-original rear gearing? or a gps? Only the gps is correct unless you've changed the driven gears in order to correct the speedo reading. The calculations, like what Fitz posted, are really all that matters to give you an idea what you'll be looking at for driveability. 3500+ rpm might sound almost "doable" or "tolerable" but it is not fun on the highway after a few trips.