Gear recommendations

[Milo3156]

I have a 69 dart with a 383, 8.75 rear end with 489-3.23 gears with posi currently with auto 727 teams. I am running 245/60/15 bfgs and would like a little more giddy up!! Was thinking about putting in 3.91 or 3.55 gears. Any recommendations for my set up? I don't typically get on the highway but I would like to be able too if needed without running 4000rpms.

I have never changed gears so not sure if I will do it or pay someone, currently it's humming really bad so there is already an issue! Would I need to change the bearings when upgrading gears? I would like think it would be smart to replace all moving parts while inside.....


Thoughts??

Thanks!!!

 

[AJ/FormS]

A healthy 383-4bbl, in a good state of tune, should smoke those 245s all the way through 1st and a good long way through 2nd with 3.23s, in your chassis.
If yours is not doing this, you need to figure out why. If it is doing this,you need to do something about that first.
So with your wanting a "little more giddy-up", I have to assume, it's not smoking the tires.if this is true, I would recommend a compression test, a cylinder leakage test, and an oil-pressure test.If these prove the engine is healthy, then I would move to checking the tune.
But you asked about numbers, so; a 3.55 would offer 10% more Giddy-up, with 10% more Rs at highway speed. A 3.91 would offer 21% more G-up, with a similar 21% more Rs.
Your current Rs at 65 are about 2650. The 3.91s would cruise around 3200, and the 3.55s would cruise around 2900. Take your pick.
If you have trouble imagining the percentages, think of it this way.If your current 383 feels like a teener, adding 10%, would put it at 350 cubes. Adding 21% would make it feel like a 385.
But if your 383 feels like a 360, then 21% more gear will make it feel like a 440.
But really, your 383 should be feeling like a 383 BEFORE you start messing with gears, and it should not be able to spin the tires all the way to 50 or 60 MPH, either.. At least that's the way I see it.
.

 

[diymirage]

A healthy 383-4bbl, in a good state of tune, should smoke those 245s all the way through 1st and a good long way through 2nd with 3.23s, in your chassis.
If yours is not doing this, you need to figure out why. If it is doing this,you need to do something about that first.

maybe that is exactly the problem, he hits the throttle and it just sits there and smokes the tires...that would keep him from giddy-up and going :burnout:

 

[Milo3156]

A healthy 383-4bbl, in a good state of tune, should smoke those 245s all the way through 1st and a good long way through 2nd with 3.23s, in your chassis.
If yours is not doing this, you need to figure out why. If it is doing this,you need to do something about that first.

Currently Not smoking tires without using line locks, waiting in the local shop to get dyno fixed to see what's going on. Then may upsize to 750cfm carb, right now I have an eddy 600cfm.

 

[273]

Anything done to the engine ?
Cam, intake, headers
Carb is probably cost a few hp but nothing serious.
Start with the basics engine health then tuning.

 

[RustyRatRod]

Even a stock 383 2 barrel would smokum in good tune. You got somethin wrong. Maybe converter?

 

[Milo3156]

Anything done to the engine ?
Cam, intake, headers
Carb is probably cost a few hp but nothing serious.
Start with the basics engine health then tuning.

Yes, intake and tti headers. Thinking about a cam this winter

 

[Milo3156]

Even a stock 383 2 barrel would smokum in good tune. You got somethin wrong. Maybe converter?

Torque converter? What could be wrong? I am not great at diagnosing but and can take stuff apart and rebuild.

 

[RustyRatRod]

Well....like we have talked about in other very recent threads, you should get what you HAVE tuned dead right first, before you spend any money. You may can get it right with some simple tuning steps.

 

[diymirage]

check to make sure you are getting full throttle movement
I had a poorly adjusted throttle cable before on a /6 and it would only open the throttle 3/4 of the way when I floored it

 

[Bad Sport]

Even a stock 383 2 barrel would smokum in good tune. You got somethin wrong. Maybe converter?

Yeah, I had a stock 383 in a Chrysler Newport and it would shred the tires.