i currently have the 3.31 gear ratio,,how much difference will i notice with the 4.10,,im sure i'll use more gas,,just wondering if the car will feel alot stronger??

i currently have the 3.31 gear ratio,,how much difference will i notice with the 4.10,,im sure i'll use more gas,,just wondering if the car will feel alot stronger?? This one change will kill your mileage. If the car has a mild cam it won't pick up much because it will push the motor out of it's ideal power band.

4.10 will kill your street manors, unless you get an overdrive.

It might "feel" stronger but chances are it won't be any quicker.
What cam/convertor are you running?
Unless your cam is like 250+ duration @ .050 and you have a 3500+ flash stall,you probably don't need 4.10's

IMO, on a true street car, the main difference would be from 0-20 MPH. Once you get going, with 3.31's your 1st gear would like second with the 4.10's. The math isn't totally true, but if I had a car that didn't have a 4500 converter and need to be maximized at the track, I agree all 4.10's will do is kill your mileage and spin the tires from a stop. Heck, I've always run 3.73's in my street strip car and on the highway it's a pain.

I have 3.31's and w/26" tires, I couldn't really keep up w/my wife the other day..she was doing 75/80. My car was real loud, and the gas guage was moving way too fast for my liking. Couldn't imagine anymore gear than this.

Unless you're building this car mostly just to play around with I wouldn't recommend going higher than 3:73's. 3:73's will get you out of the hole a lot quicker and won't totally destroy your higher speed driving. I wouldn't use 4:10's unless it was for a car that would be seeing most of it's time on the strip. The only exception here would be if you're running a 6 speed gearbox such as a T-56.

What do you use the car for? Everyday to and from work? Weekends only? etc.

Most of my cars are driven within the city in 45 MPH zones and under..usually on weekends. I love deep gears in this case.

If you have to drive on the interstate or fairly long distances I'd stick with the 3.31s.

In the 1986 I had a '69 SS 396 Chevelle with a healthy tunnel rammed 331, M22 and 4.56s that ran 11.56 @ 119(x race car 3000lbs.). I drove this car everyday everywhere including 30 miles to and from work.

But I was 20 then. :D

What do you use the car for? Everyday to and from work? Weekends only? etc.

Most of my cars are driven within the city in 45 MPH zones and under..usually on weekends. I love deep gears in this case.

If you have to drive on the interstate or fairly long distances I'd stick with the 3.31s.

In the 1986 I had a '69 SS 396 Chevelle with a healthy tunnel rammed 331, M22 and 4.56s that ran 11.56 @ 119(x race car 3000lbs.). I drove this car everyday everywhere including 30 miles to and from work.

But I was 20 then. :D

the car is used only on the weekend ,,driven no more than 100 miles a weekend,,used just mostly to show off,,the car feels sluggish with the 3.31s,,,i might end up going with 3.73s,,

Thats what I have in my '69. Xcellent all around gear.:thumbsup:

Well, I'll chime in.

I say go with the 4:10's.

I have a 67 that probably weights 3700 pounds and I think a heavy car needs alot of gear.

I run a SBC with a 232/242 hyd. roller cam. My rear tires were 26 inchers and they would just fry. I put on some 28 inchers and it helped alot.

I cruise around 3000 at 60 mph. Its not to bad at freeway speeds.

My car is a weekend car also. I may visit the strip 1 to 2 times a year. I drive it maybe 50 to 75 miles a weekend. If that is all you drive it, reguardless of type of driving, I think the 4:10's would pay off.

Like I mentioned a heavy car needs alot of gear to get it going. Reguardless of strip or street, if you want to have fun then you need a reasonable amount of gear.

Now if you are just a cruiser and want to go shows and never "get on it" Then a 3:31 or something would be the key.

the car feels sluggish with the 3.31s

What cam do you have? Convertor ? What is your base and total timing?
Most street/mild strip cars I know of get by fine with 3.31-3.55 gear
My old 1970 442 clone runs high 11's @ 115 MPH with 3.31 gears and a 27" tall tire (best of a 1.66 60 ft. with 3.31's too)
Heck,I went a 12.99 with 2.56's with a mild 454

You don't need 4.10's :)
3.73 is the steepest I would go,and I would run a 275/60 tire.


I like passing fellow gearheads that ride around with 4.10's on the highway :D
Heavy cars need torque,not gear

Chris

i agree with you.

BUT

A chevelle with a SBC (less than a 383) will need alot of gear to get it moving.

BUT

Are not chevelles mainly a BBC deal?

Torque and gear ( torque multiplication) are on the same side of the equation, one can compensate and offset the other.

The trouble with the 4.10s is that, for street, you run out of gear too quick. That's why so many go to 4 sp autos and 5/6 sp manuals.

Run out of gear in the 1/4 right? That is the reason I went with a 28 inch tire, to give me more rpms in the 1/4. With the 26 inchers, I was at my redline in the 1/4.

4:10's @ 60mph can be anywhere from approx 3200 with tall tires to 3600rmp short tires,anyway you look at it carp for any street drining.

You will need a fairly stout high winding motor to take advantage of 410 gear.

Be smart and drop in a set up used 3:55's but the 373s will turn approx 3,000-3,200 rpm at 60mph if you can stand it . To me anything over 3:73 is crazy for street IMHO unless you have an 8 second ground pounder and you dont have that kind of setup.

You best bet is go for a drive in someones car that has 4;10 & 3:73 gear to see what its like before changing to it.

I went from 3:07 to 3:31 and it was a very noticeable jump/increase in perf so if you went to 3:55's it would be a very good inc rease in perf & the motor could likely stiil handle that much of a gear change. But going from 3;31 to 3:73 or 4:10 will push your motor too much past cam/rpm capabilty and it not street friendy gear too that i bet you will get tired of in 1 season IMHO.

I would go for 3:42 or 3:55's max unless you plan on a motor performance upgrade soon to handle the additional gear and driving a lot less on the street like 30 -40miles a wk end.

Scott

Go with 3.73s.They are the ULTIMATE street gear.I run them in my 69 with 28 inch tall tire and its turning 2900 at 65 m.ph. exactly.Now that aint high revving at all.The car takes off like a bat out of hell and still can go on the freeway.You will be much more happier with 3.73s than 4.10s trust me.3.55s.3.42s,3.31s and 3.08s are not that impressive out of the hole.The 3.73 gear set is one of,if not, the most common used gear choice among responsive well built street cars.2900 revs at 65 mph with 28 inch tall tire aint nothing to a well built motor.

3.55s.3.42s,3.31s and 3.08s are not that impressive out of the hole

IMHO, a 1.66 60 ft. with 3.31's and a 275/60 drag radial is quite impressive! :)

Go with 3.73s.They are the ULTIMATE street gear.I run them in my 69 with 28 inch tall tire and its turning 2900 at 65 m.ph. exactly.Now that aint high revving at all.The car takes off like a bat out of hell and still can go on the freeway.You will be much more happier with 3.73s than 4.10s trust me.3.55s.3.42s,3.31s and 3.08s are not that impressive out of the hole.The 3.73 gear set is one of,if not, the most common used gear choice among responsive well built street cars.2900 revs at 65 mph with 28 inch tall tire aint nothing to a well built motor.

yeah the 3.31s in my car feel sluggish,,although the car a pretty good sized Lunati cam,,it still doesnt have that pep off the line,,,so im hopin that if i change it to the 3.73 i will notice a BIG difference

What is your combo?

Tell us everything from motor, tranny, rear gear, tire size, car weight and etc.

Everyone has giving great advise here. Lets try not to over analyze.

Weekend Car.

Big Block.

3.73s.





Priceless! :D

396ci, Lunati cam ,eldebrock intake and holley 780 carb, bored to a 402, stock th400 with 2000 stall, tire size 255/60/15 in the rear, current 3.31, not sure of the weight ( close to stock i guess),,,,,im think in i should go with the 3.73,,that gear should give it more pep off the line

Do you have any idea of the cams spec's? Cam spec's has alot to do with gear selection.

Another truth is the more power you have, the less gear you need. My son's nitrous car has 3.50s and 28" tires.

there isnt that much difference in a 3.73 and a 4.10,,a quarter a turn more with a 4.10

Where do you have the timing set at? With you tire size an 331's it should be a tire burner, unless the cam is way to big for your compression.

I currently have 4.10's with 26'' tire. Driving @ 50 mph is starting to drive me nuts. I will drop down to 3.73 or 3.55 and go with 28'' tire.

JC70SS, try and just change the tires first. I had the same setup as you do and I switched to the 28 inchers and it was very helpful. I think if you drop to a 3.55 AND a 28 tire your cruise at 60 mph will probably be 2000 or so. May take you out of your cam powerband. Youn don't want to be cruising and the motor wanting to "lope."

JC70,i also run 26 inch tall tires,i would drop back to 3:55's ,you will still have plenty of go and it will be a nice relief/drop in rpm going from 4:10 to 3:55.

You will use a little less fuel along with less motor wear & tear,less noise,and less underhood heat too but still have enough gear for some fun when you get into it.

I my 396 turns approx 2,600rpms @ 60mph with 26inch tall tires,3:31s'/12 bolt & m20.

Scott

Scott

You make some great points.

The problem as I see it are:

1. How big of tires do you want?
2. Tranny issues -- 4 speed / auto
3. Cam issues

What a person is running here dicates the gear.

Here’s my vote:

Cruising use 273 or 308
Racing use 373 or 410
Compromise use 331 or 355

i think i may save some money over the winter and get a good clutch and go with a 4-speed

I went right past it and use 4:56 on the street(bbc). Of course it sees 7000 rpm more frequently than most......

If you go 4 speed, the first gear ratio in a M21 or M22 is 2.20. You are going to need a 3.55 or BETTER rear gear to help with the shallow 1st gear.

Automatics have a deeper first gear as well as the 5 and 6 manuel speed trannys.

I use to use a 3.08 with a M-21 and I had to slip the clutch a little to get it moving.

Car weight, tranny, and torque ability of motor all decide the rear gear selection.

After that is decided, then the intended use of the car comes into play.

One of the local guys runs 3.08 gears and a powerglide in a 66 Chevelle.

Drives an hour and a half to the track.

Runs 12.1 to 12.2 at a 2600 foot elevation track.

To me that is pretty impressive.

Another guy with 3.25 gears in a Olds runs 12.0's with 3.25 gears.

Basically heavy cars in full street trim.

Over the winter I am going to swap out the 4.1 gears for a set of 3.25's in my Beaumont. Easy enough cause it has a 9 inch. And use a quality 10 inch converter instead of the el cheapo 12 inch. The 4.1 gears are brutal on the street especially with a short 26 inch street tire.

Those are impressive!

Are those automatic cars? That might explain it a little.

26 inchers and 4:10 are MURDER!

Motor power might explains it also.

Motor torque, that is.

I stepped up from 3:31 to 3:73 and with no other change droped ET and MPH.
May of been the air or any number of little things, but there was now real change.

I went from 2.73's 13.5@101.7 best ET (only used 1st &2nd) to 3.73's with a best of 13.2@103.25 with no changes and heads stopped breathing @ about 5500. New heads fixed that.
3300rpm @ 60mph with 27" tires,300 10" stall,th350.

I have 4.11's in my 69 Chevelle SS, and it turns 3400 rpm's at 65 mph. I have 3.73's in my 85 GMC, and I turn 3000 rpm's at 65 mph. These both wear currently BFG 275/60/15's for street driving. My truck went from 3.42's to 3.73's. If you are going to drive on alot of highway, I would not go any higher than 3.73's, and at times wish I had the 3.42's back in the truck, but I sure like the way it scoots from a standstill.

My chevelle, I will keep the 4.11's in it.

I ran 4.10's in my '66 from 1982 until last year. Even though the car is primarily a street terror, 20-30 mile freeway jaunts (each way) are not unusual. I found that I cruised more often than not, in excess of 4000 rpm. Still the average Hyundai could blow by you. Sure, a little pressure to the go pedal, they magically re-appear in the rearview mirror, BUT, inevitably you must lift. Again, the Hyundai goes passed, this time a lane further over and on a cell phone, reporting a wreckless driver (take your pick road rage; drunk; epileptic; turrets).

I went from 3.08's to the 4.10's. At the time, I fully expected a revelation off the line, what I found was negligible launch improvement (tires spin faster...WOO WOO). This coincided with going off to school (actually pulled the 4.10 12 bolt posi out of a '66 El Camino in a Phoenix Wrecking Yard) during which the Chevelle made 2 trips to Phoenix. Fortunately the speed limit was still 55 mph (3000+rpm), which translates to 5 hours straight spinning nearer 4500rpm (I can't drive 55). I was glad to stop for fuel every hour, besides stopping eyeball vibration, the car required the regular once over (you cut alot of corners when your 18 years old). I referred to any road trip to 24 hours of Daytona.....Nonetheless, I endured 23 years of procrastination and 4.10's.....

Right before Christmas of 2004, I was wrapping up a much delayed rebuild, (the result of an Oct. 2002 accident), which required the rearend axle tubes to be indexed (out of alignment). Teardown revealed a bent axle and 2 broken spider gears. I inquired into different gears, but ended up reusing the 4.10's in a new #4 carrier. I had finished up the car with a 10 bolt posi under it that had 3.73's. The 12 bolt sat for 7 months on the garage floor while I continued to drive on the 10 bolt.

Finally, I loaded up the 12 bolt and took it back to the same shop, having it changed to 3.55. The new #4 carrier was swapped straight across for a new #3 carrier at no charge (thankfully, I never even filled it with gear oil), but my procrstination cost me several hundred $'s, otherwise avoidable had I not suffered from "Rectal, Cranial Inversion" (head up my rear).

I am very glad that I bit the bullet, especially now that I went to the 540. The bottomline, unless running a dedicated race tire (slick), any reasonably powerful big block should overcome street tires (on or off track), virtually negating advantages generally associated with taller gears.

For what it's worth, 3.55=3000-3200rpm @ 70 mph

4.10 is to much if you have to do much highway driving. I have to drive 15 minutes or so into town. With 4.10 and 26" tire 4000 rpm was like 65 mph and not keeping up to traffic. Put the 3.42s back in and the car is a dream. It's quiter. I don't need to worry if I can make it home with only 1/4 tank of gas.
It still will spin the tire more than I need to.

275/60/15's on the back !!! I'm in the same situation, although much more seriuos, see in my signature, but with the carrier i have it says i have to stay min the 4's, being a 4:10 the lowest i can go. Part # MOR-83000

im thinking of going with a 3.73 and a good 4-speed tranny

I don't know how anyone could stand driving 4:10s for any distance.
The highest (numerical ratio) gears I have in any of my cars is the 3.42s in my 1969 Buick Sportwagon (455, TH-400). Even that was too much gear, so I added a Gear Vendors overdrive. Now I run 2,500 rpm @ 80 mph ! :)

I think with a 3-speed automatic and no overdrive, the best all-around ratio is 3.31 .

Ran 3.31's behind my hyd. cammed 302, th400, 26" tire, '68 Camaro. Although I always thought it was undergeared, it ran about low 14's. Drove it daily. With the 406, convertor stalls at 4400, 1000 more than planned, and with 10X28" tires, it launches hard. My initial plan was to add nitrous, so 3.31 is still a good gear, not that far from ideal. Stick with 3.31. Is it a posi? That will make huge difference in luanch with higher ratio gears. I really think, that with the broader torque from cams these days, coupled with high stall convertors, low gears are no longer the necessity they once were.

There are only three ways to make horsepower: increase BMEP, increase RPM, or cut friction. 40 years ago, the only route readily available was to increase RPM, and hope you could just maintain the torque. Modern cams, plus more roller grinds, help keep the RPM's down while still improving performance. It just keeps getting better!

My first DZ had 3.73's and a 2.2 Muncie; would go 70MPH in 1st gear. 2.2 1st gear was not the best plan for those cars. 2.5 would have been a much better choice. For those of you that can't remember, original Z28's ran in the low 15's off the show room floor. Ambitious tuning of the stock parts would put them in the mid 12's. Headers were a must. Mine went 6600 RPM in high gear with 1 1/4" valve springs. It could be done. Cam was broken-in 30-30 with Isky valve springs, 140 LBS on the seat. Today I would have no qualms about putting that much pressure on a cam that had been broken in with light springs, like 70-80#.

Put your car in second gear and leave it there and see if you like it because it'll feel close to that.

2 cool,i was just going to suggest the same thing,ride aound in 2nd gear all day and see if he likes that.

4:10's are usless on the street without some kind of overdrive unit or overdirve gear in a man trans to drop the cruise rpm down some IMHO.

I also feel 3;73 are very marginal for street use too unless you run something like od etc to drop cruise rpm down a little but the 4:10s are just crazy with out overdrive of some sort.

Maybe he needs to dial in his timing and carb better to wake up his BBC. With 3;31 gear it should do ok unless he is being unrealisitc in his expectations compairing it to a friends 502 or hot 454,just wont match that ,there is no replacment for cubes in NA non assisted motor.

Scott

I live rural & chose very quickly to go from 4.10s to 3.36s!

Speed limit cruise (50 mph) lowered my rpm by 500 :hurray:
now that don't sound like much but as pointed out early when that Hyundi goes by at 70-80 & you run her up to 4000 for a while to keep up I get nervious real fast :sad:

Even 3.36s as far as I'm concerned are just highway friendly enough to get you there.

Granted my combo is a M-21 4sp w/255/60x15s, but now 3rd with 3.36s is almost exactely what 4th was!
Or on the flip side 2nd with 4.10s is almost exactly what 1st is now with 3.36s. I can live with my slightly tall out of the hole gearing, in my opinion a M-20 would fit my demands almost perfectly :hurray:

Maybe he needs to dial in his timing and carb better to wake up his BBC.


..thats what I'm thinking.My 454 combo was quite impressive (IMHO) even when I had 2.56's,so a mild 402 with 3.31's dialed in should be more than fun to drive.