Audiophobe

I want more highway drivability for my 58 with 4:11. It runs about 3200-3400rpm at 60mph.
I am looking to buy a 3:55.
-Anyone have an opinion as to the best all around driving ratio?
Thanks



(I'm trying to get in touch with a forum member now to buy. It's hard to find one! Chicago Corvette has great deals but I was told to stay away.)

midyearvette

i like a 336 with a wide ratio 4 speed....

1snake

That's what I have in my 65. I just pulled the 4.11's out of my 60 (close ratio 4 speed) and installed 3.70's. Perfect all-around combination.

Jim

Pilot Dan

This subject has been talked about a lot before. I had a 3.55 and as far as highway driving, it still did not give me a low enough RPM. Put a 3.08 in and am very pleased now. You will get lot's of different replies and it comes down to personal preference. I also tried a 3.36 before the 3.55. Wide ratio for sure! Pilot Dan

wmf62

, unless there is a 5spd in your future..... but, it also depends on how much lowend torque your engine has; what are you using as an engine?
Bill

BarryK

i'm not so sure there is a simple "one answer" to your question. A lot will depend on the gear ratios you have in your tranny and the HP/TQ of your motor.

For example, on my '65 I have 4.11 rear gears which do make a pretty lousy highway gear BUT my stock L76 365hp motor with the 30-30 cam is notorious for it's lack of low-end torque so the 4.11 is practically a requirement just to get the thing off the line.
On the other hand, if your motor produces more torque than you could go with a higher (lower number numerically) rear gear making highway driving a lot more pleasant.

If you have the torque and tranny gear ratios to make it work, a 3.08 or 3.36 would make a great highway gear.
If you dropped in a 5-speed tranny you might even be able to go to a 2.73 rear.

wmf62

Barry
one would have to have a 'torque monster' big block for an engine to pull a 2.73 w/OD. with my .73 OD and a 2.73 rer, it would be effectively a 1.99; it wouldn't even come close to the ZZ4's curve except maybe about 100...
Bill

MikeM

From reading posts here on this forum about OD transmissions, I think this particular fact is often overlooked.

I think a 327/365 with even a 3.08 axle and no OD would be a sorry combination at anything less than a dollar's worth on the highway. And that's illegal almost everywhere!

Frankie the Fink

My 3.70 wasn't awful to start with but the addition of the Tremec 5 spd just made it perfect....a 'deeper' 1st gear and effortless highway cruising in OD 5th gear. Perfect.

wmf62

my 350/370 LT1 (a kissin cousin to the 327/365) was only tolerable with a wide ratio muncie and a 3.55rer til i installed the MY6 with a 3.09 1st gear and then it became driveable. when i changed to a 3.36 it was back to just tolerable and if it hadn't been for the 3.09 1st it would have been a BIG mistake...... thank God for FI; with a carb it would have been next to impossible.....

i still think the 1st gear ratio x the rearend ratio rule of thumb should be 10 or above for decent driveability.

the ZZ4 seems to be happy as it has a low flat torque curve.....

Bill

blue63cpe

A my6 is a 4sp but 4th is od not 1/1 and 1st to 3rd are standared muncie? To the OP, bite the bullet and get a 5sp.

BarryK

Bill, i understand what you are saying but..... for a few years I had a '78 I picked in back in '06. had the L82 higher performance motor (high performance being relative to '78 of course - it was only 220hp).
I don't remember now without looking at my info on the car when I get back home but I THOUGHT the standard rear gear ratios were 2.73 standard and 3.08 as a higher performance gear but I very well may be wrong and am forgetting the real info in which case I apologize for the incorrect info.
Generally I agree with you that a 2.73 is going to be pretty high gearing and going to be tough getting off the line but for highway cruising it sure would give a nice low rpm. Maybe with a 5 or 6 speed it could be usable??
In the OP's case a 3.08 or 3.36 is going to be better but I still say it depends on his motor and tranny combo

RoadKing96

I think there needs to be a couple questions answered first.
What I might like isn't necessarily what you might like or be looking for.

• What motor / hp ?
• What type of driving (highway / street)?
• What average speeds ?
• Burnouts / Cruising ?
• Tranny (Wide / Close)?
• Tranny (4spd / 5 spd)?
• Is gas mileage a concern ?

To me, your answers to these, can lead to a more accurate answer.

RK

MikeM

Barry,

The SHP engines of the '50's/'60's did not like to run with high gearing, whether it be off the line or cruising. That's why in most cases the standard gear was 3.70.

When you run those engines getting at least close to the point of max torque (3000-3500 rpm), they have good throttle response and acceleration plus acceptable fuel milage. If you try and choke them down to a lower rpm, they do none of the former very well at all.

If you have a standard 250/300 hp engine, they'll accept the higher gears a lot better.

tach drive 61

dan were we drive on GS parkway 60 MPH is a threat to life 75 is a safe bet !, you need the 308 set LOL I have them all the 308 set is packed away the 370 set it great for my 61 , for local fun this spring i will use the 411 posi unit.I have a wide ratio T 10// PS fathers day long branch show will be the slow way RT 35 and a gas stop with the 4:11 set I look foward to that show see you there i hope dan .

midyearvette

back in the day, you would order at least a 3:70 with a close box and the smart guys bought the 4:11's
you are right about the sweet spot in around 3000 rpm and most did not care about freeway cruising....
then again, you use a wide box behind those heavy cammed engines and really change the driver comfort with a taller gear
the problem was the rpm drop in 4th and ironically, the taller you went with the gear, the more it dropped the torque below the sweet spot on the 3rd to 4th shift....unless of course you wound it tighter in 3rd....

66BBCoupe

I love 3:70's with a close ratio - perfect for the type of street driving that I do

Sky65

I have considered a 2.73 rear. I have a 3.08 now. Key is the Richmond non-overdrive 5 spd trans. 3.27 1st gear and 1:1 5th.

6T5RUSH

Really like the "jump" with my wide box and 3.73:1 posi rear. DON'T like buzzin' when I try to cruise on long trips above 65 mph. Frankie's right about getting that perfect match via a 5 speed using my 3.73's. I'm slowly getting off the fence to migrating in this direction.



Jim
In God We Trust!

DansYellow66

Another vote for the 3.70 ratio.