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Discussion Starter #1
In the near future, I am gonna get a set of gears for my '68 standard. I am thinking in the 3.55-3:73 range. I dont want to get to radical, just quicken it up a bit.

My question is....what do I need to change to do this? Do I just get a new ring and pinion or do I need to replace the carrier (I think that is what is called).
What about posi? Is it worth it for the street? What are my options?

I did a quick search here and didnt find much of what I was looking for.

As always, thanks for educatin' me!
 

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You can buy whatever gears you want for whatever you have. To make posi, the conventional/"regular" way of doing this involves changing the carrier. I do not recommend the non-conventional ways. For this too you can buy whatever you want for what you have. If you are doing any of this, the conventional wisdom is to do it to a 9 inch. If you don't have one, you might want one (especially if you like performance). Beyond this advice I would only say think long and hard (and PLEASE, do some research) on the gears you are thinking about. If your plans do not include overdrive in the trans, you are going to (in the end) HATE the gear ratio range you are enamored with. Some things to think about.

Regards,

Bob
 

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This kinda a new area for me to but from what I have read on here if he changes the rear end ratio doesn't the speedometer gear also need to be changed? Also I have read that certain cams work with certain rear ends? Haven't quite figured that one out myself yet.
 

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This kinda a new area for me to but from what I have read on here if he changes the rear end ratio doesn't the speedometer gear also need to be changed? Also I have read that certain cams work with certain rear ends? Haven't quite figured that one out myself yet.
Yes, good point Harv. For a given rear gear, one needs to get the proper driven gear to end up with an accurate speedo reading (often overlooked/ignored/tolerated). Now regarding the gears and cam, it is fairly simple, if you want to run an attention getting lopey idle cam, this pretty much always means the power producing part of the RPM curve is shifted toward the high end of the RPM range. To take advantage of this, tall (high numercial) gears are installed. The problem is that at cruising speed on the highway, the fillings in your teeth will tend to rattle out from the winding of you engine (unless you have aforementioned OD). But with OD comes lower revs (good), and lower revs with a cam with the "look at me" sound = crappy perfomance due to the "power band" mismatch with the rear gears (bad).

How's that, clear as mud? Made perfect sense to me! :buck:
 

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Discussion Starter #5
My end product will not be a daily driver but a fun to drive cool car. It will be a car that I have always wanted. It will have the "look at me sound" so I will need a gear ratio to compliment it. I am definitely gonna spend my money wisely and do my research.
 

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Actually yeah I kinda understood that. same as keeping in the power band on a bike. wrong gear or wrong rpms no power! never put a cam in that equation though.
 

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Andy,

I have a 1967, 289 - C4 Cougar. It had a 3:00 open (non posi) rear. I had the engine warmed up a bit with a Comp Cams Extreme energy cam and some pretty serious head work & bigger valves. Comp cams said the cam would perform best with a rear gear between 3:25 & 4:11. I went to Don at WCCC and got a 3:40 rear gear with posi. I was able to get the right speedo gear at my local Ford dealer. By the way, this is an eight inch rear end and I'm told it will hold all the power I can get out of the 289. I am very pleased with the performance of the old cat:evil:

Paul
 

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Discussion Starter #8
Paul, that's kinda what I learned a long time ago w/ my chevy. I was told that my 10 bolt would be fine for what I wanted to do. I suspect the same would be true for the 8 inch. I am on a LIMITED budget so I need to get the most bang for the buck. My planned operating range will be from 1500-5500 rpm.
 

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Andy You can have the "look at me sound" which in my opinion is a big part of having a fun to drive cool car and a daily driver in one package. Like Old man says get stuff that works together. 3:50s would be fine for a warmed over stock motor.
 

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Discussion Starter #10
So I guess the only other question that I will have (after i decide on gear ratio) is to either just put new taller gears in my open rear end or save for a trac-loc setup. Is a trac-loc worth the wait (saving the money, $1000.00)?
 
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