4:11 rear end ... Anyone?

[Andy4639]

U will not be happy on the interstate with 4:11 with a 350 turbo!

My 71 with 305 and 700-r4 is 2300RPM @ 70 MPH. I have 20" wheels. Gas milage want matter because the exit's are close enough you can stop at each one to fill up!

[capev86]

on my 72 Burb C20 (307, 3 on the tree), i switched from the original 4.57 to a 4.10 gear (my truck has the corp/eaton axle that swaps like a Ford 9 inch). i'm not wasting any extra rpm's thanks to the solid connection of a clutch. at 60mph i'm turning 3,000 rpm, so highway driving still isn't much fun. i just bought a 3spd manual + overdrive on here and with the .7 o/d ratio i will be down to 2100rpm at 60.

the 3.07 is WAAAAY too soft for a truck unless you have a monster engine or a diesel, never tow and spend all your time on the highway. i would recommend something around a 3.42 AND overdrive for a highway cruiser. my dad's 99 burb (2wd) loves this combo.

a 4.11 with overdrive will be better on the highway than a straight 3.07 and you get good pulling power. anyone with a turbo 350 trans should look into a 200-4r because it is the same length and it has a better o/d ratio (.67 instead of .7) than the 700-r4 which will be good with a steep rear gear like a 4.11. i would have gone this route with 72 Burb if it had been an automatic.

[68Stepbed]

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<

A Muncie still has a 1:1 final ratio like the bulldog trans you have now. The TH400 is also a 1:1 final drive ratio, but without a lockup converter, so rpm will be 200-300 rpm higher than with a manual trans

[eightbanger]

If an overdrive unit like gear vendors was fitted, would that give you the best of both worlds?....keeping torque and good RPM's on the freeway.

[Longhorn 70]

when I had the 350/350 turbo I got 13 mpg and was around 3000 rpm as I recall. Then went to a 425 olds and 400 turbo and got around 11-12 mpg with the same rpm.
I also had a granny 4 speed with the 425 and got about the same mileage.
Now get 15+ with the 425/700R4. I turn 2100 at 65 MPH. The tranny gets me out of the hole better than the 350 turbo or 400 turbo as well.

I calibrated the speedo as well as I could each time by timing a mile and using calculators. These figures may be off a bit but they are close.

[ole86chebby]

you can always just run a taller tire to reduce the gear ratio

[capev86]

If an overdrive unit like gear vendors was fitted, would that give you the best of both worlds?....keeping torque and good RPM's on the freeway.

i would go with a transmission with overdrive first. when you consider the price of a Gear Vendors unit (plus all the mods to the drive train) coupled with the fact that the overdrive ratio isn't very much (.85 vs. .7 or better) it just doesn't make sense in most cases. these units are tough as nails, but they were intended for older motor homes (that didn't come with an overdrive trans) or trucks that are always towing a big load and need a compromise between economy and power.

[67basketcase]

I would gladly trade you a set of 3.73 for your 4.11. I'm in Michigan too PM if interested.

[jocko]

Originally Posted by eightbanger

If an overdrive unit like gear vendors was fitted, would that give you the best of both worlds?....keeping torque and good RPM's on the freeway.

The GV o/u unit would split each gear, so:

Your current 1st gear is what it is, no change
You will have a new intermediate gear between 1st and 2nd if you choose to split all gears
Your high gear will now have an o/d gear above it (i.e. the new high gear).

So, to answer your question, your off the line performance is unchanged but your highway cruising rpms drop per the o/d ratio.

You could IMPROVE low end torque multiplication and o/d cruising with a trans swap (if it has a deeper 1st gear, which most do) but a GV unit will not provide improvements on both ends of the spectrum, just the high gear end.

[SS Tim]

Plus with the G/V splitting gears on a manual it is a clutchless shift like an automatic. That is great when you are pulling a load as it keeps the power on and the engine in the power band. You don't have the 1-2 hole that the low first of a 700R4 gives you.

[eightbanger]

Cheers for the info Jocko...much appreciated

[Fitz]

Originally Posted by capev86

i would go with a transmission with overdrive first. when you consider the price of a Gear Vendors unit (plus all the mods to the drive train) coupled with the fact that the overdrive ratio isn't very much (.85 vs. .7 or better) it just doesn't make sense in most cases. these units are tough as nails, but they were intended for older motor homes (that didn't come with an overdrive trans) or trucks that are always towing a big load and need a compromise between economy and power.

They were also intended for DRAG RACING. Johnny Winter (that's JWR Racing for the uninitiated) recommends the gear vendors 0.7:1 unit behind a built turbo 400 instread of the 200R4, 700R4 or any of the newer computer controlled transmissions on applications upward of 400 Hp/400 ft-lbs of torque because of the increased reliability. My current setup hits over 600 hp and 600 ft-lbs of torque and there is simply no way to build an overdrive trans that will live very long with that much torque passing through it. Besides, gear splitting makes the turbo 400 act like a 6 speed! Lot's more fun.

[JOJABOY]

Originally Posted by Bishop73

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

I am in the boat as well. I have TH400 and 4.10 in my C20. I have been debating on tranny swap or re-ringing the rearend. My TH400 is solid and since the Dana 60 has the floating axles....I am leaning toward a higher gear for the back.

To the OP....with my TH400 and 4.10 combo I am cranking out some serious RPMs to hold it at 60 on the freeway.

[DropKick]

ah Yes , I have a Original 80's Ford F350 Dually Rear end in my 69 cst 10 Its got Factory 4:11 Gears in it , I havent yet ran it on the road due to Engine swap so i Cant answer many questions about the ride

[exploderjim]

I would be interested in the 4.11 complete rear end if you want to sell. PM me if interested.

[dukcaln]

hate my gear set up, sucks even for around town..... changing soon

[montoya22]

thanks bud. would you suggest a rear end swap? i do have a 3.73 rear end that came out of a late 70's blazer just laying around. and i have a 3.07 my buddy would sell me for next to nothing. however i still would like to have a 5 speed (t5).. have one out of a s15 but idk if it would hold up to my 350. let me know bud and thank again for your imput.

[montoya22]

Originally Posted by 68Stepbed

A Muncie still has a 1:1 final ratio like the bulldog trans you have now. The TH400 is also a 1:1 final drive ratio, but without a lockup converter, so rpm will be 200-300 rpm higher than with a manual trans

thanks bud. would you suggest a rear end swap? i do have a 3.73 rear end that came out of a late 70's blazer just laying around. and i have a 3.07 my buddy would sell me for next to nothing. however i still would like to have a 5 speed (t5).. have one out of a s15 but idk if it would hold up to my 350. let me know bud and thank again for your imput.

[70c10stepside]

I have 4.11 with turbo 400. Got to actually drive it today, for the first time. Has a built up 355. I went back roads on the way to town, turning 2300 rpm the entire way. Gas gauge didn't move a bit. On the way back, I got curious and hopped on the main road on the way back. About 14 miles of 55( roughly 3200rpm). I could look down every couple minutes and the gauge would have moved down a tad. And the screaming of the loud exhaust had my ears bleeding.


I've got to do something in the future, or stick to back roads lol
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[derrickmanx1]

I've got 4.10's and a 4l80e. I'm hoping to be at 2600-2800 rpm @70 27" tall tire. I will know next month when I drive it. I'd do a gear vendor or an overdrive and be done with it.

[LT102]

Here's a website that has an RPM calculator based upon transmission, tire size and rearend ratio combination.

http://www.chevellestuff.com/tools/rpm_calculator.htm

[bugmasta]

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