ways to lessen weight?
#21
4.11 gears on a big block Chev engine would be a huge mistake! We're not talking a SBC engine that can easily wind 6,000 rpm's. A big block wont wind that kind of rpm often without a lot of work, and with 4.11 gears you'll be constantly running way above the ideal rpm range for a BBC. That BBC will be screaming just running down the freeway at 65 mph, and with average freeway speeds in Wa. being 60-70 mph, you'll wear that engine out quickly.
I've run everything from 4.56 down to 2.73 gears in my Camaro, and presently I'm running 3.42 gears. I would not recommend going any lower than maybe 3.73 and the 3.38-3.42 range is ideal in my opinion for a car that does mostly street duty, with a fairly well built engine.
Considering the torque, and HP of the engine you're looking at, you don't need low gears to make up for anything.
I've run everything from 4.56 down to 2.73 gears in my Camaro, and presently I'm running 3.42 gears. I would not recommend going any lower than maybe 3.73 and the 3.38-3.42 range is ideal in my opinion for a car that does mostly street duty, with a fairly well built engine.
Considering the torque, and HP of the engine you're looking at, you don't need low gears to make up for anything.
#22
even though the 454's peak hp is at 6k and peak torque is 5000 with a cam that makes its power between 1800-6000?
I'm also going to get a 700r4 tranny to help with highway driving, wouldn't that help keep the rpm's down enough on the highway with 3.73-4.11 gears?
I'm also going to get a 700r4 tranny to help with highway driving, wouldn't that help keep the rpm's down enough on the highway with 3.73-4.11 gears?
Last edited by jason7504; 12-09-2009 at 07:07 PM.
#23
Just becaue a BB engine makes peak HP at 6,000 doesn't mean you should run it up there a lot. Cruising down the freeway holding a constant RPM of around 3,000 will eventually take it's toll on your nice new engine. Do you want it to really run hard for a few years, or last you for a long time?
The 4:11 gears will wind right up there, and get you there a little quicker, but it's not a longevity situation. If you want the engine to last, and get your money's worth of miles out of it, I wouldn't go over 3:73, even with a 700R4.
The 4:11 gears will wind right up there, and get you there a little quicker, but it's not a longevity situation. If you want the engine to last, and get your money's worth of miles out of it, I wouldn't go over 3:73, even with a 700R4.
#25
4.11 gears on a big block Chev engine would be a huge mistake! We're not talking a SBC engine that can easily wind 6,000 rpm's. A big block wont wind that kind of rpm often without a lot of work, and with 4.11 gears you'll be constantly running way above the ideal rpm range for a BBC. That BBC will be screaming just running down the freeway at 65 mph, and with average freeway speeds in Wa. being 60-70 mph, you'll wear that engine out quickly.
I've run everything from 4.56 down to 2.73 gears in my Camaro, and presently I'm running 3.42 gears. I would not recommend going any lower than maybe 3.73 and the 3.38-3.42 range is ideal in my opinion for a car that does mostly street duty, with a fairly well built engine.
Considering the torque, and HP of the engine you're looking at, you don't need low gears to make up for anything.
I've run everything from 4.56 down to 2.73 gears in my Camaro, and presently I'm running 3.42 gears. I would not recommend going any lower than maybe 3.73 and the 3.38-3.42 range is ideal in my opinion for a car that does mostly street duty, with a fairly well built engine.
Considering the torque, and HP of the engine you're looking at, you don't need low gears to make up for anything.
Again, it really all depends on what your main intentions for the car are.
Last edited by CamaroGuy71; 12-09-2009 at 10:07 PM.
#26
It also depends on what trans he has. If it was a close ratio 4-speed then yeah, it would be bad running really low gears, but if its a wide ratio trans (like a lot of them in the 70's), then he'll probably want to gear it down some. Maybe not down to 4.11, but I'd go down to the 3.73 if it was wide ratio, and if its the close ratio, then 3.38 is really all thats necessary. I dont know if that year is like the early 2nd gens, but most came with a 3.08 which is really high geared.
Again, it really all depends on what your main intentions for the car are.
Again, it really all depends on what your main intentions for the car are.
its gonna be mostly street and some strip
#27
It also depends on what trans he has. If it was a close ratio 4-speed then yeah, it would be bad running really low gears, but if its a wide ratio trans (like a lot of them in the 70's), then he'll probably want to gear it down some. Maybe not down to 4.11, but I'd go down to the 3.73 if it was wide ratio, and if its the close ratio, then 3.38 is really all thats necessary. I dont know if that year is like the early 2nd gens, but most came with a 3.08 which is really high geared.
Again, it really all depends on what your main intentions for the car are.
Again, it really all depends on what your main intentions for the car are.
Same thing with the 700R4. It really doesn't matter if it has a 3.06 first gear, or a 2.06 first gear when it comes to cruisin speed. What rpm you will have in top gear at freeway speed is crucial to longevity of the motor.
Use whatever motor and rear axle ratio you want. I'm just trying to relate my own experience from trying a lot of various gears and combinations, to tell you what works, so you don't have to make the same mistakes. With 4:56 gears I couldn't finish the 1/4 mile without overwinding my engine. 4:11 were the same; just too close to redline and that's not good in high gear. Redline is different on the engine in 1st or 2nd, than it is in high gear. There's lots more load on the engine, and you don't want to be up there for long.
I found the 3:73's were optimum for 1/4 mile drags, but still made my engine wind too tight for freeway driving. Sure a overdrive trans would help, but it's still only .8 overdrive, so you reduce your rpm's by 20%. That means if you're running around 3200 rpm you'll reduce it 640 rpm's to 2560. Not much of a reduction.
With my large rear tires, and the 3.42 rear gears I cruise at 65 at around 2200. I think that's just about perfect for a big block Chevy.
Last edited by 1971BB427; 12-09-2009 at 10:51 PM.
#28
Wide ratio or close ratio makes no difference when you get to 4th gear. Both types have a 1 to 1 4th gear, so there's no difference at that point. The rpm's in 1,2,3 gears will be different, and in those gears you are correct, but still he'd have cruising issues with any 4spd. stick.
Same thing with the 700R4. It really doesn't matter if it has a 3.06 first gear, or a 2.06 first gear when it comes to cruisin speed. What rpm you will have in top gear at freeway speed is crucial to longevity of the motor.
Use whatever motor and rear axle ratio you want. I'm just trying to relate my own experience from trying a lot of various gears and combinations, to tell you what works, so you don't have to make the same mistakes. With 4:56 gears I couldn't finish the 1/4 mile without overwinding my engine. 4:11 were the same; just too close to redline and that's not good in high gear. Redline is different on the engine in 1st or 2nd, than it is in high gear. There's lots more load on the engine, and you don't want to be up there for long.
I found the 3:73's were optimum for 1/4 mile drags, but still made my engine wind too tight for freeway driving. Sure a overdrive trans would help, but it's still only .8 overdrive, so you reduce your rpm's by 20%. That means if you're running around 3200 rpm you'll reduce it 640 rpm's to 2560. Not much of a reduction.
With my large rear tires, and the 3.42 rear gears I cruise at 65 at around 2200. I think that's just about perfect for a big block Chevy.
Same thing with the 700R4. It really doesn't matter if it has a 3.06 first gear, or a 2.06 first gear when it comes to cruisin speed. What rpm you will have in top gear at freeway speed is crucial to longevity of the motor.
Use whatever motor and rear axle ratio you want. I'm just trying to relate my own experience from trying a lot of various gears and combinations, to tell you what works, so you don't have to make the same mistakes. With 4:56 gears I couldn't finish the 1/4 mile without overwinding my engine. 4:11 were the same; just too close to redline and that's not good in high gear. Redline is different on the engine in 1st or 2nd, than it is in high gear. There's lots more load on the engine, and you don't want to be up there for long.
I found the 3:73's were optimum for 1/4 mile drags, but still made my engine wind too tight for freeway driving. Sure a overdrive trans would help, but it's still only .8 overdrive, so you reduce your rpm's by 20%. That means if you're running around 3200 rpm you'll reduce it 640 rpm's to 2560. Not much of a reduction.
With my large rear tires, and the 3.42 rear gears I cruise at 65 at around 2200. I think that's just about perfect for a big block Chevy.
And while we're on the topic, do you think 4.11's would be too low for a 350 or 383 too? I mean I realize SBC's can rev higher.
#29
Wide ratio or close ratio makes no difference when you get to 4th gear. Both types have a 1 to 1 4th gear, so there's no difference at that point. The rpm's in 1,2,3 gears will be different, and in those gears you are correct, but still he'd have cruising issues with any 4spd. stick.
Same thing with the 700R4. It really doesn't matter if it has a 3.06 first gear, or a 2.06 first gear when it comes to cruisin speed. What rpm you will have in top gear at freeway speed is crucial to longevity of the motor.
Use whatever motor and rear axle ratio you want. I'm just trying to relate my own experience from trying a lot of various gears and combinations, to tell you what works, so you don't have to make the same mistakes. With 4:56 gears I couldn't finish the 1/4 mile without overwinding my engine. 4:11 were the same; just too close to redline and that's not good in high gear. Redline is different on the engine in 1st or 2nd, than it is in high gear. There's lots more load on the engine, and you don't want to be up there for long.
I found the 3:73's were optimum for 1/4 mile drags, but still made my engine wind too tight for freeway driving. Sure a overdrive trans would help, but it's still only .8 overdrive, so you reduce your rpm's by 20%. That means if you're running around 3200 rpm you'll reduce it 640 rpm's to 2560. Not much of a reduction.
With my large rear tires, and the 3.42 rear gears I cruise at 65 at around 2200. I think that's just about perfect for a big block Chevy.
Same thing with the 700R4. It really doesn't matter if it has a 3.06 first gear, or a 2.06 first gear when it comes to cruisin speed. What rpm you will have in top gear at freeway speed is crucial to longevity of the motor.
Use whatever motor and rear axle ratio you want. I'm just trying to relate my own experience from trying a lot of various gears and combinations, to tell you what works, so you don't have to make the same mistakes. With 4:56 gears I couldn't finish the 1/4 mile without overwinding my engine. 4:11 were the same; just too close to redline and that's not good in high gear. Redline is different on the engine in 1st or 2nd, than it is in high gear. There's lots more load on the engine, and you don't want to be up there for long.
I found the 3:73's were optimum for 1/4 mile drags, but still made my engine wind too tight for freeway driving. Sure a overdrive trans would help, but it's still only .8 overdrive, so you reduce your rpm's by 20%. That means if you're running around 3200 rpm you'll reduce it 640 rpm's to 2560. Not much of a reduction.
With my large rear tires, and the 3.42 rear gears I cruise at 65 at around 2200. I think that's just about perfect for a big block Chevy.
do you think that would still rev too high on the freeway?
yeah i appricate that your trying to help me so i dont mess up either You do have a point about the gear ratio with a BB though. don't want it to overrev and I do plan on doing 1/4 mi drag when i do go to the strip so maybe i will go with 3.73 gears, that should be good with the .70 OD gear right? i also plan on getting 10" wide rear tires later on too
#30
i believe 4.11's would work for a SB as long as you dont do much freeway driving since it will be kinda hard on the engine and your wallet lol