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-   -   going from 3.73 to 3.08 affecting my stall speed (

snakebit68 03-02-2013 01:29 PM

Gear ratio
The gear change will certainly inprove fuel mileage, but it will kill performance. It wont really effect the stall speed of your convertor, but you will lose low end performance. It will become a little more street friendly. I must say that 4600 stall on the street isnt recommended though. Are you sure of that stall? Its awfully steep. I run an all out race truck with a stall in that neighborhood, but wouldnt dream of running it on the street.

ap72 03-02-2013 01:30 PM

Changing gears won't save you gas and won't have a dramatic effect on trap speed. Your change is very very small. You may want to consider a cam and stall change instead.

snakebit68 03-02-2013 01:36 PM

Gear ratio
I agree with that. A cam change and stall change would be the best way to make it more street friendly

camaro 68 03-03-2013 07:00 AM

going from 3.73 to 3.08 affecting my stall speed
Hi :welcome: my post got deleted :( don't know why?? but here it is again,

I've been thinking of changing my gear from 3.73 to 3.08, but don't know if it's going to make a big difference on my stall convertor or if it still going to be happy. I would like to know if someone here did it or could tell me what to expect from this change....maybe to wide of a change maybe? Doing more and more street and less drag.

Right now it is stalling right at 4600rpm with the 3.73 with 30 inch tire and th400 behind 496ci.

Luc's now want to save gas and going a bit slower.... :-)
Camaro 68 3470 pounds
496ci 10.5:1 3.73
Edelbrock oval 290cc
825cfm on Strip Dominator
10.50 at 131mph 1.45 60ft

delawarebill 03-03-2013 07:16 AM

i don't feel u will see much or any difference. your not make a major difference in ratio's.. now if u went from 572 to 308 u would see something.. but u've got a large stall...

496CHEVY3100 03-03-2013 07:25 AM

Any time you add weight ,increase torque ,not horsepower,you will change stall ,example being before stall converters were avalible at every corner we used Vega converters ,the wer rated at 2200 in 4 cyl vege when behind a good sbc probagly in 3500 range a BBC even more in a camaro.there probably wont be a Big difference but you are a gearhead you will see some that the average Joe might not ,,the 308 should work fine.:thumbup:

F-BIRD'88 03-03-2013 08:15 AM

The stall speed will not change but the car will spend a longer time "on the converter" as you accelerate.
The converter will be loaded, longer.

You won't gain fuel mileage just by slowing the motor down. Its a hi perf motor. It wants to rev. You will gain more in fuel mileage by improving the tune of the engine to use the fuel better, in the rpm range used now.

Carb, (the idle and cruise circuit) distributor (vacuum advance), intake manifold. (a dual plane is a lot more efficient at the cruise rpm)

Of course if you cannot keep your foot out of it, don;t expect a real net fuel consumption reduction.

camaro 68 03-03-2013 10:01 AM

Thanks for your posting;)

Now it all make sense, will stay on the converter longer with the 3.08.

I will probably be doing the converter and gear together to make most of it.
Will have to call ATI to see how they charge for a reconfiguration?

Thanks :D

68NovaSS 03-03-2013 10:19 AM


Originally Posted by camaro 68 (Post 1652878)
Hi :welcome: my post got deleted :( don't know why?? but here it is again

It wasn't deleted, look down the thread list, it was moved to the trans/differential forum, there's a redirect in place.

Moving this post as well and will merge the two.

camaro 68 03-03-2013 10:41 AM

I am wondering if changing the stall would make a bigger and better difference?
Maybe reconfigure to something like 3500rpm instead of 4600rpm maybe this would be a better choose? What do you think:confused:


OneMoreTime 03-03-2013 12:37 PM

If you were to get in the way-back machine we made a gear change like that in search of a better launch. the taller gears meant less wheelspin and the car may leave harder. Of course with the taller gears the freeway cruise is a bit nicer. I woudl not concern my self with changing the torque convertor at all..


496CHEVY3100 03-03-2013 02:08 PM

Are you talking stalling at 4600 ,or flashing at 4600 ,either way lowering to 3500 will let it run cooler ( less slipage ) 308 will lower rpm which always helps mileage contrart to some beliefs .

F-BIRD'88 03-03-2013 04:07 PM

Kinda makes ya wish it had the stock 250 hp 327 in it again.

All you are going to achieve is making the car slower.
and the converter and car will seem even more sluggish at small throttle inputs.
and you will have spent all that money for nothing.

When you figure that out, just remember I told you so.
The gears and converter are not the problem.

camaro 68 03-03-2013 04:15 PM

thanks 496chevy,

great people on this site:cool:

the converter flash at 4600rpm. it is very good, it's a 9 inch treemaster from ATI, it is tight for the street also. I may ask them to reconfigure it to arroung 3500rpm. I think it will be even more effecient at 3500rpm.

When I complete the work (arround june), I will will let you people know the result.


496CHEVY3100 03-03-2013 04:40 PM

Lookin forward to hear from your results.

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