[The Champ]

Originally Posted by Formulajones

We daily drive one of our stick cars. It had 8.94 1st gear multiplication. I can tell you that after about 20k miles of daily use, clutch chatter starts to set in. It's not bad but it's there, and that's just a 3400 lbs. car. I find that torque multiplication right around 10 to be a sweet spot for any combination. Torque has nothing to do with it.

With a lot less torque than even a mild 455, the factory sent these cars out with effective gear ratios of around 8 or lower.

Maybe it's your driving style that requires an effective ratio of 10 or more...

Like Tom, I'm running a healthy 462 and switched from 3.42's to 3.08's AFTER installing the 462, with the plan to eventually upgrade from my original M20 to an M23Z.

Effective 1st gear ratio is now 7.88 vs the 8.76 previously. Barely noticed the difference.

When I upgrade the tranny, I'll have an effective first gear of 9.21 which would equate to running a 3.60 rear end with my original M20...

[Half-Inch Stud]

470 CID 9.0:1 2500 rpm at 75 MPH. Teens* initial with 34* Total at 2600 rpm. 3.54:1 27.5" tire
87 Octane Street, 89 Octane Strip.

Able to pull away in 3rd without lugging.
Sometimes pull away in OD 4th when i forget to downshift. Minor lugging butt hey it goes.

37" long by 5" dia Collector Extensions to prevent REVERSION.

[Tom Vaught]

If you remove the clutch disc at some point, and glass bead the surfaces to remove the resin "glue" on the surface of the disc that builds up over time, you can easily get 3 times the mileage out of the life of the disc and the clutch system will not slip or chatter as you mentioned. The clutch chatter is caused by the resin in the clutch material boiling off over time and adhering to the surface of the disc. I have never had a clutch chatter even after hundreds of 5,000 launches and thousands and thousands of street miles once I did the mod the first time.

Again Thanks Del Forrest, WW-II Mechanics Instructor and Chief Mechanic at my uncle's Pontiac Dealership.

Tom V.

Champ, Formulajones has his opinions and we have our opinions.
Looking forward to the Trans Installation on your vehicle down the road.

[Formulajones]

Originally Posted by Half-Inch Stud

470 CID 9.0:1 2500 rpm at 75 MPH. Teens* initial with 34* Total at 2600 rpm. 3.54:1 27.5" tire
87 Octane Street, 89 Octane Strip.

Able to pull away in 3rd without lugging.
Sometimes pull away in OD 4th when i forget to downshift. Minor lugging butt hey it goes.

37" long by 5" dia Collector Extensions to prevent REVERSION.

Automatic is a completely different deal. You have a torque converter that creates gear multiplication for you.

[Formulajones]

Originally Posted by The Champ

With a lot less torque than even a mild 455, the factory sent these cars out with effective gear ratios of around 8 or lower.

Maybe it's your driving style that requires an effective ratio of 10 or more...

Like Tom, I'm running a healthy 462 and switched from 3.42's to 3.08's AFTER installing the 462, with the plan to eventually upgrade from my original M20 to an M23Z.

Effective 1st gear ratio is now 7.88 vs the 8.76 previously. Barely noticed the difference.

When I upgrade the tranny, I'll have an effective first gear of 9.21 which would equate to running a 3.60 rear end with my original M20...

I'm well aware of the factory gear ratios and how the cars were built. I have a couple of them here with 2.20's and 3.55 rears. They suck plain and simple. In reality GM didn't practice that a lot and to be honest, it's just not a very good daily driver setup. It's just not. It's harder on clutches and anyone that daily drives these things will tell you that. It has nothing to do with driving style. As an example, one of our daily drivers, has had 3 different people in the family drive it on a regular basis, and they'll tell you the same thing.

Now if you can't tell the difference from 7.88 to 8.76, almost a full ratio, something is wrong. That's a big swing. That tells me you're not grasping the concept I'm explaining. When you do your upgrade making your effective 9.21, that's not horrible and it's livable. More in the range where GM built 100's of thousands of cars. It'll work, and make things livable, but it's still not near the realm of an overdrive setup and low rpm cruising which is what this thread was about.

Most everyone here doesn't daily drive this stuff so you really have to take a lot of these opinions with a grain of salt. A couple thousand miles a year on their classics really isn't enough to truly evaluate. Day in and day out putting the car in every possible scenario that most of your classics on here never see anymore will really change your perspective on what works well and what's not that great. Drive a 2.20/3.55 setup daily for 2-3 years, log 25-30,000 miles, Then jump in something with a 2.87/3.55 setup for another 2-3 years ever day, then come back and tell me you don't notice a difference. Tell me then which one was more of a pleasure to drive in traffic, starting on hills and grades. Which one did your wife jump in and like better.
I'll bet money I know your answer.

[David Jones]

Tuning for an OD can be a learning experience. My 455/TKO/3.73 is turning approx 2000/2100 rpm at 70mph and seems happy in it's work. I've found I can run it down to about 45 mph in OD, depending on the situation. That's in the 12-1300ish rpm range. I try to limit that activity, since shifting gears isn't that tough.

At some point soon we'll hear about the high strung small block Chevy that regularly chugs along at 850 rpm.........

[389]

Boy you guys like to make a toy complicated..

-Use a 068 or SD10 cam for torque off idle.
-Turbo 400 built for street duty not drag strip!! Good luck finding somebody who can build it for you, there out there but very hard to find..
-Use a tall rear end ratio to compliment the 1:1 final gear ratio and the stator of the "street duty" converter (no drag converters!!)..
-Hurst Autostick I shifter. Cable shifters ruin all the fun of clutch-less shifting. The Autostick is directly linked and bolted to the transmission.. The shifts are so positive much like the M22 ...

[The Champ]

Originally Posted by Formulajones

I'm well aware of the factory gear ratios and how the cars were built. I have a couple of them here with 2.20's and 3.55 rears. They suck plain and simple. In reality GM didn't practice that a lot and to be honest, it's just not a very good daily driver setup. It's just not. It's harder on clutches and anyone that daily drives these things will tell you that. It has nothing to do with driving style.

I drove military sedans over in Germany for three years as a classified courier and logged over 50,000 miles.

Full size Chevy or Rambler cars with 3 on the tree manual transmissions (GM Saginaw has a 2.54 1st gear, Warner in the Rambler was similar). These cars all had an economy rear end in them - so most likely a 2.73 or 3.08 for the Chevys and equivalent for the Ramblers.

Considering I needed to drive on the autobahn, I needed those long gears to keep up with the flow of traffic.

The first car I owned after getting married in 1973 was a '67 Biscayne with a 3 on the tree and an economy rear gear.

My first new car was a '76 Ventura with a 3spd manual floor shift with the standard rear end.

Let's just suffice it to say I've got plenty of experience driving manual transmissions as daily drivers and haven't had the negative experiences you claim to be having.

[geeteeohguy]

Originally Posted by Chief of the 60's

If you have the right carb setting and the right gear ratio there is no modification needed to the timing. 2300 RPM @ 70 MPH tells me the gear ratio is wrong causing the engine to load up. Think of it like driving a stick in 4th gear and doing 25 MPH. A lot of bad things go on when RPM's are too low for the MPH. Good RPM for 70 MPH should be 2650 - 2800 RPM with an O.D.

This is not true. RPM's can be too low and cause a car to lug, but 2300 at 70 ain't even close. A stock 068 cam makes decent power from about 1500 RPM to redline. I've been driving my '76 GTO for the past 12-15 years with a 2.56 rear gear and a TH400.....probably 25,000 -30,000 miles. Burns no oil, doesn't eat plugs, and when I did the re-seal on it (close to 90k miles on my '80's rebuild) the bearings looked like new. I run at 2450 rpm (80 mph) and get 21 mpg at that speed. Running 65 at around 2100, I get 23 mpg. If I were running 1200 rpm at 70 I would be 'off the cam' and out of the powerband, and maybe lugging the engine. But it's only a 400, and it does fine hauling the tall gear. The line 'a good RPM for 70 mph should be 2650-2800 RPM with O,D" means that your OD isn't working. That's much too high. My car without OD cruises 90 mph at 3,000 rpm all day long if I want.

[Formulajones]

Originally Posted by The Champ

I drove military sedans over in Germany for three years as a classified courier and logged over 50,000 miles.

Full size Chevy or Rambler cars with 3 on the tree manual transmissions (GM Saginaw has a 2.54 1st gear, Warner in the Rambler was similar). These cars all had an economy rear end in them - so most likely a 2.73 or 3.08 for the Chevys and equivalent for the Ramblers.

Considering I needed to drive on the autobahn, I needed those long gears to keep up with the flow of traffic.

The first car I owned after getting married in 1973 was a '67 Biscayne with a 3 on the tree and an economy rear gear.

My first new car was a '76 Ventura with a 3spd manual floor shift with the standard rear end.

Let's just suffice it to say I've got plenty of experience driving manual transmissions as daily drivers and haven't had the negative experiences you claim to be having.

Then I'll just say this....

I've installed a zillion of these swaps in various cars for people. I haven't had one person yet that came back and told me they couldn't notice a difference with gear multiplication or complained about any aspect of the swap for that matter. They've all praised the ease of drivability and the improvements it has provided and most tell me they kick themselves for not doing it sooner. Zero negativity.

Now from reading your posts, you've clearly progressed with the 1st gear ratio and have plans to increase it yet again, which tells me you do realize the benefits or you wouldn't be spending the money.

So you're in one of 2 categories.... Either you're an odd duck that can't tell a change, even a drastic full point change, and believe there is no need or benefit from it, but you do it anyway, which would put you by yourself in a very large group of people that I know,

Or you're just lying to me, not wanting to admit there is a change and a benefit there, even when the math is showing a drastic change. I think people can read this and decide for themselves.

[Formulajones]

Originally Posted by 389

Boy you guys like to make a toy complicated..

-Use a 068 or SD10 cam for torque off idle.
-Turbo 400 built for street duty not drag strip!! Good luck finding somebody who can build it for you, there out there but very hard to find..
-Use a tall rear end ratio to compliment the 1:1 final gear ratio and the stator of the "street duty" converter (no drag converters!!)..
-Hurst Autostick I shifter. Cable shifters ruin all the fun of clutch-less shifting. The Autostick is directly linked and bolted to the transmission.. The shifts are so positive much like the M22 ...

So basically build a stock car and drive it,

Automatics make these decisions much easier when you have a torque converter between the engine and trans. It's a completely different ball game. You can run a 2.29 rear gear in it and forget about it if you want freeway cruising. 1st gear multiplication and daily drivability doesn't care about a clutch disc when you have a torque converter. Just don't expect to win anything at the stop light grand prix. Fine for a daily driver though.

Stick shifts are a different animal, and so many people try to play the game with a 4 speed of 1st gear multiplication while trying to keep a somewhat highway friendly ratio in the rearend. It's cat and mouse and can only be really good at one end or the other, not both. Some settle on a compromise that makes them happy, and that's fine. I personally would rather not compromise and be good on both ends of the spectrum. The only real way to do that is with an overdrive transmission. The OEM figured this out decades ago. Which gets back to what this thread is about. Very low RPM cruising and tuning for MPG. You need an overdrive to experience any of that.

[Formulajones]

Originally Posted by David Jones

Tuning for an OD can be a learning experience. My 455/TKO/3.73 is turning approx 2000/2100 rpm at 70mph and seems happy in it's work. I've found I can run it down to about 45 mph in OD, depending on the situation. That's in the 12-1300ish rpm range. I try to limit that activity, since shifting gears isn't that tough.

At some point soon we'll hear about the high strung small block Chevy that regularly chugs along at 850 rpm.........

Bring yourself out West David and I'll show you how it's done

[The Champ]

Originally Posted by Formulajones

So you're in one of 2 categories.... Either you're an odd duck that can't tell a change, even a drastic full point change, and believe there is no need or benefit from it, but you do it anyway, which would put you by yourself in a very large group of people that I know.

Or you're just lying to me, not wanting to admit there is a change and a benefit there, even when the math is showing a drastic change. I think people can read this and decide for themselves.

First of all, I never said I couldn't tell the change between 3.42's and 3.08's, just that it wasn't much of a change. My post on that said, "Barely noticed the difference."

Here your claiming that a less than 1 point change (it was .88) is DRASTIC. But you also claim that going to the M23Z where the change will be well over 1 point (1.32 to be exact), you said, "When you do your upgrade making your effective 9.21, that's not horrible and it's livable."

So on one end a less than 1 point change is "DRASTIC" and on the other hand a 1.32 change is just "LIVEABLE"???

My motivation to switch to the M23Z is due to the fact that my M20 should get a full rebuilt after 50+ years of driving and the M23Z is a much stronger transmission that happens to have a lower 1st gear.

When I did the gear swap several years ago, I was prepared to do the tranny swap right away if it was necessary. As the change was not dramatic, I decided to get a few more years out of my M20 before making the change.

What I save on the rebuild will reduce the price of the M23Z by 30 - 50%. It's a simple bolt in replacement - no fabrication needed.

Back in the day, the "hot" setup was an M22 and 3.90's or 4.11's. 4.11's would be a 9.04 effective first gear ratio and 3.90's would be 8.58.

When I make my swap, I'll have a stronger tranny than the M22 and an effective 1st gear ration of 9.21. Better than the "hot setup",and a highway gear to boot.

As to your lying claim - that is insulting.

You keep contradicting yourself and it appears you're getting frustrated as you are resorting to personal attacks.

I'm happy your customers are happy with your work.

I thought long and hard about a 5spd OD swap, but I don't want to hack up my car and I want to keep my original Hurst shifter and console.

[Tom Vaught]

Originally Posted by Formulajones

Then I'll just say this....

I've installed a zillion of these swaps in various cars for people. I haven't had one person yet that came back and told me they couldn't notice a difference with gear multiplication or complained about any aspect of the swap for that matter. They've all praised the ease of drivability and the improvements it has provided and most tell me they kick themselves for not doing it sooner. Zero negativity.

Champ, let it go. Anything people say they have done stuff a Zillion times without a complaint you know it is pure BS. Post up a real number for people and then the real experiences come out. Example like when we had the discussion about removing the oil pan with the engine in the car and I posted I had done it 3 times at my Uncle's dealership. Are you more likely to believe me or the guy who has removed the pan a ZILLION TIMES.

I read a lot of those statements on the board. Your comments are well founded on the autobahn experience as typically you ran thru the gears one time and then cruised with the traffic until you reached the city you wanted to go to. All of that gear multiplication BS means nothing in that driving mode.

Tom V.

[Formulajones]

Originally Posted by The Champ

First of all, I never said I couldn't tell the change between 3.42's and 3.08's, just that it wasn't much of a change. My post on that said, "Barely noticed the difference."

Here your claiming that a less than 1 point change (it was .88) is DRASTIC. But you also claim that going to the M23Z where the change will be well over 1 point (1.32 to be exact), you said, "When you do your upgrade making your effective 9.21, that's not horrible and it's livable."

So on one end a less than 1 point change is "DRASTIC" and on the other hand a 1.32 change is just "LIVEABLE"???

My motivation to switch to the M23Z is due to the fact that my M20 should get a full rebuilt after 50+ years of driving and the M23Z is a much stronger transmission that happens to have a lower 1st gear.

When I did the gear swap several years ago, I was prepared to do the tranny swap right away if it was necessary. As the change was not dramatic, I decided to get a few more years out of my M20 before making the change.

What I save on the rebuild will reduce the price of the M23Z by 30 - 50%. It's a simple bolt in replacement - no fabrication needed.

Back in the day, the "hot" setup was an M22 and 3.90's or 4.11's. 4.11's would be a 9.04 effective first gear ratio and 3.90's would be 8.58.

When I make my swap, I'll have a stronger tranny than the M22 and an effective 1st gear ration of 9.21. Better than the "hot setup",and a highway gear to boot.

As to your lying claim - that is insulting.

You keep contradicting yourself and it appears you're getting frustrated as you are resorting to personal attacks.

I'm happy your customers are happy with your work.

I thought long and hard about a 5spd OD swap, but I don't want to hack up my car and I want to keep my original Hurst shifter and console.

No personal attacking, I'm just calling it as I read it here. You've kept making improvements on the first gear multiplication and planning to do more, but you're telling me at the same time it doesn't matter. Apparently you like the idea. Personally I don't care what you do with your car so no frustration on my part, I'm just trying to keep the conversation real with good data points for the sake of this board and the people reading. Driving military vehicles and buzzing up and down the autobahn has nothing to do with our discussion.

My comment of being livable is referring to the overall affect and what I consider acceptable. It's not a bad ratio for a daily driver, it's livable. I just prefer a little more, but that's all you're going to get sticking with a 4 speed while trying to keep the rear gear highway friendly. That's just the way it is.

The 1 point is a drastic change was meant towards your comment of changing almost a full point and stating you hardly noticed a difference. I know better than that. Taking things out of context without reading the entire paragraph, or reading through a few posts loses it's meaning.

But it's all good on my end, don't get ruffled. Doing your car the way you like it is all the matters. We are free to point out the faults, it helps everyone make their own decision. That's what discussion forums are for.

[Formulajones]

Originally Posted by Tom Vaught

Anything people say they have done stuff a Zillion times without a complaint you know it is pure BS. Post up a real number for people and then the real experiences come out. Example like when we had the discussion about removing the oil pan with the engine in the car and I posted I had done it 3 times at my Uncle's dealership. Are you more likely to believe me or the guy who has removed the pan a ZILLION TIMES.

Tom V.

The Zillion comment is purely meant to get the point across, and you know that, you just want to be the way you always are on this forum. The point is I'm pretty sure I've done more overdrive swaps in classics than the majority of the hobbyists on the forum, so I do have maybe just a little experience in that area. You're welcome to your opinion, but that's all it is.

I've offered a ton of advice and swap tricks to get these transmissions in the cars without cutting or chopping things through PM's and emails in the past. If that's someone's only excuse to skip installing one of these things they missed the opportunity.

[PontiacJim1959]

Once again, the original theme of the post has steered far, far, away to left of center.

Why is the M23Z even being brought into the conversation when it is not an overdrive? Am I missing something?

What is being missed here are a number of factors. First factor is the driver. Some people simply should never own a manual transmission, period. Just because they can let out a clutch and shift a gear or two does not mean they can drive one.

A big factor is horsepower/torque. I don't need a super low 1st gear matched to any specific rear axle ratio. Give me a 2.56 rear gear and 400HP and I'd simply slip the disc to get the car rolling. I guarantee someone else would simply stall the engine, over, and over, and over...... because they do not know how to drive a manual trans. Those are the same people who when on a steep grade or hill and sitting at a stop light can't take off cleanly and stall the engine, roll back, hit the brake, try again and repeat until the green light turns red or they roll back into your car.

Give me a 2.56 rear gear and a 180HP 283CI in an Impala, and you have a real challenge on your hands. Why, because the next factor is weight. A 3.08 rear gear could be a challenge for many whereas a 3.23 or 3.36 with a low 1st gear ratio has proven to be a much better combo for the average driver.

Seeing I drive a tractor-trailer, try pulling off a steep grade on a hill from a dead stop with 80,000 lbs. Wow, how do I do it? This is a normal expectation, but in today's world were more cars have automatics than manual transmissions, the average driver doesn't know how to shift anymore ..........and many of the trucks on the road today have Allison automatics.

The weight of the flywheel, clutch disc material and type, and pressure plate clamping pressure and type also have a huge factor in take-off and comfort level. The weight of the flywheel builds inertia and this factors into how well it'll keep the rotational mass in the engine spinning when you let out the clutch. A heavier flywheel is more forgiving than something light like an aluminum flywheel. Some discs will slip far better than others because they are purpose built. Same goes with the pressure plates - some are very easy to push in & out, but may not hold well in higher HP applications. Then you have the pressure plates that require a leg and your arm to hold your leg in place, but they will clamp the clutch disc so it'll never slip. My guess is many select a clutch set-up that is more than what they need and the results speak for themselves - they work real well, grab hard & fast, but the driver blames the gearing of the driveline because as soon as they let out the clutch it grabs fast & hard and the engine stalls - they did not understand what they were buying.........because it was recommended by a friend who had a supercharged Big Block and his clutch set-up never slips.

Yep, having a 2.87 or 3.27 1st gear and 3.55 and up rear gears are a cinch to make a get away - how can you not? You could just let out the clutch and you would be hard pressed to stall an engine out, and if you did, you don't need a manual trans car.

But the original post is about Overdrives, not 4-speeds which of themselves presents a limiting factor because you cannot take advantage of a rear gear like 3.73, 3.90, 4.11, or 4.56's which will make any 1st gear 4-speed ratio work, but is not practical at most modern highway speeds that the general public run at which is 70-80 MPH, regardless of the posted speed limits.

And that's where the Overdrive come into play, whether an automatic or a manual transmission. Shooting for a cruising RPM in Overdrive is a personal choice as to what numbers you prefer to see or are comfortable driving at. Sure, your cam choice and converter stall have to be considered when building for all out HP and higher RPM's in the range you plan on cruising around in. With an OD, I can't see it unreasonable to be cruising between 1,900-2,300 RPM at speeds of 70-75 MPH. I have read how some feel 2,600-2,800 RPM's is fine, but all that does is accelerate wear, cause a hotter engine, and eat up more fuel. Then the counterpoint becomes, "but that was what these car's ran at when new." And my return comment is, "and that's why they wore out early or blew engines."

So I think it is fair to say that lowered RPM's won't hurt an engine as long as it is built somewhat near stock, or in the range of 400-450HP. Lowered RPM's may hurt a car that has been built wherein the engine pieces are not a match for lower RPM's to begin with and require a higher RPM to work as intended - such as big CFM heads, high lift cams, & big carbs. An Overdrive can be the best solution of both worlds, zippy fast accelerations through a combination of first gear ratio's and rear gear ratio's, and then putting the trans into OD where it can loaf along and still have the torque to pull the car comfortably down the road.

It has always been my experience with every car I have ever driven from the 1950's-1970's is that when lugging the engine, you can get detonation, and conversely, when you get detonation, you are typically lugging the engine. The solution was to adjust the timing. Today timing seems to be associated with the gas quality, but I used to adjust my timing based on lugging the engine upon acceleration and then pulling over to the roadside and moving the distributor as many times as needed to get the detonation out. And detonation is where damage to the bearings comes into play if long term or violent detonation is allowed to continue..........and not from running the engine at lower RPM's.

At least that is how I see it.

[Formulajones]

And that right there is what these forums should be about. Everyone weighs in with their experiences, good or bad, with various opinions from others as to what has worked for them and what hasn't, leaving emotions and egos out of it, so that people can read this, see both sides and come to their own conclusion, and make an informed decision that will work best for them.

[Formulajones]

Originally Posted by PontiacJim1959

An Overdrive can be the best solution of both worlds, zippy fast accelerations through a combination of first gear ratio's and rear gear ratio's, and then putting the trans into OD where it can loaf along and still have the torque to pull the car comfortably down the road.

[Tom Vaught]

Originally Posted by Formulajones

No personal attacking, I'm just calling it as I read it here. Doing your car the way you like it is all the matters. We are free to point out the faults, it helps everyone make their own decision. That's what discussion forums are for.

One of my bosses used to say, "one piece of data is worth 1000 opinions".

Champ knows what his vehicle like. He has data on that vehicle.
I have data on my vehicle and know the type of driving I do and what I can
be happy with. Unless the two drivelines and vehicles are exactly the same there is no capability for arguing one way or the other.

Using words like Faults is another example of you using your opinion as far as what is a fault. Maybe is perfectly acceptable for the next guy. And the internet and someone posting in a forum does not allow you to be a JUDGE on whether their selection of parts is a fault or not. My way or the highway is the wrong approach, technically or personally. My Nash trans is like a optimized 1st gear muncie with a shifter position that (with a 2.75 rear) simulates a 4 speed with overdrive EXCEPT IT IS A LOT STRONGER.

Tom V.