New rear end

Questions about all other brand differentials.
Islanddean
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New rear end

Postby Islanddean » Wed Jan 31, 2018 11:23 am

Hey guys
I have a 67 Camaro with a 327 engine and a TH350 tranny. The rear end is an original 10 bolt but im not sure what the gear ratio is. The original tranny was a 2 speed PG. I can stand on the throttle and the tires won’t spin.

IM wanting a new posi Trac rear end but have no idea where to start. What gear ratio is best, do I install an entire new rear end or rebuild what I have? Also...the current rear end has drum brakes and I want to change to disc. I want to be able to light up the tires when the young punks pull up beside me.

Please keep in mind that I have absolutely no clue about differentials and am not a mechanic. I can do brake jobs and other light work but when it comes to jobs like this I have no idea what I’m doing

Thank you I’m advance for any help/direction you can give me.

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monzaz
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Location: RICHFIELD, OH

Re: New rear end

Postby monzaz » Sat Feb 03, 2018 6:32 pm

No Name??? Here we go...
PLEASE do not take this the wrong way BUT we get this all the time ...Guys what to do burn outs and they right away assume it is because of gear ratio.

IT IS NOT...

2.56 or 5.57 you should be able to spin the tires with a V8 car.

If you can not...You need to look at the motor first. WHY does ther car have NO LOW END torque?
- old and tired?
- ignition timing not working correctly or set correctly?
- Carb not adjusted correctly?
- Too big a cam shaft?
-Torque converter to low stall?
Gear only enhance what you already have... If you want quicker acceleration then gears are the away to go in the steeper catagory.(3.73 4.10 )
Freeway driving and gas mileage higher ratio (2.56 2.73)

Now since you have a power glide your actually missing a lower gear then a 350th or 400th will have to give more torque to the rear wheels. BUT if you go gears steeper to try and solve a BURN out condition you do not have the car will be useless in all other areas of driving. 1.76 1st gear and 1 to 1 final in the trans with a power glide ...1 to 1 means your driving the rear gear ratio 2.56 or 4.56 or other.
350th first gear is 2.52 and the 400th is 2.48...multiply that by the rear end gear ratio of even 2.56 and you get 5.00 ratio in first gear.
power glide would be 1.76+2.56 = 4.32 which still should be enough for a 327 to spin the rear wheels.

THEN tire size also comes into play with rear gear ratio...smaller tire give the effect of more steeper ratio and a tall larger diameter tire will effectively give to a higher more freeway gear ratio effect.

Now if you can not spin the rear wheels POSI will do absolutely nothing for you.

So we have to figure out why your car does not have engine torque?

Can you tell us anything about the motor ? or is it another well I bought it this way cars??? :(

AGAIN...this happens ALL TIME...you are not the first one.

Heads?
Carb type?
Intake?
Ignition type?
Has anything been done to anything?

Jim Mitschke
J D RAce
J D Race

Islanddean
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Posts: 3
Joined: Fri Jan 19, 2018 10:15 am
Location: Oklahoma City

Re: New rear end

Postby Islanddean » Sat Feb 03, 2018 9:29 pm

I certainly didnt mean to bring up a touchy subject. I was directed to this website from the guys over at Camaros.net and thought I could find a few answers here.

wish I could answer all your questions but the fact is I am NOT a mechanic. While I did rebuild the front end, rebuilt the entire brake system and even rebuilt the Edelbrock carb plus a few other systems I have absolutely no idea about those topics you mentioned.

All I know is when I stand on the throttle the back tire won’t spin. At first I wrote this off as the problem being the gears for the PG tranny but after reading your response it sounds like the old girl just may be tired.

I’ll try to research each point you made one by one and hopefully I’ll be able to figure this out.

Islanddean
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Posts: 3
Joined: Fri Jan 19, 2018 10:15 am
Location: Oklahoma City

Re: New rear end

Postby Islanddean » Sat Feb 03, 2018 9:29 pm

By the way...my name is Rusty

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monzaz
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Re: New rear end

Postby monzaz » Mon Feb 05, 2018 10:26 am

Rusty....No, that is not what was meant and the reason writing does not sometimes send the correct message...lol. I mean that this is a common trouble with most and you should not feel like your the only one and or embarrassed of it.

Everyone wants to hope the engine is good and other things are just not set-up to do the job...Just because a Motor starts and runs does not mean that it is running to its potential by any means.

Try a compression check on the motor. That is fairly no money easy check on the cylinders to see what the motor is pushing .
Leak down compression test will give an idea if the valves are shot which can not be determine buy just looking .

Heads are the biggest culprit of lack of torque and power.
IF someone had done some work on the motor it could have had TOO big a came installed - too much duration overlap which make the motor should tough and lumpy on the idle will cause the motor to have any low end power because it is a race type cam shaft.

So when you stomp on the gas does the car distinctly pick-up after a CERTAIN rpm (LIKE A SET OF THE PANTS DEFINITE TORQUE INCREASE FROM THE INITIAL STOP AT THE BEGINNING) OR JUST THE SAME FROM THE BEGINNING TO THE END OF YOUR ACCEL RUN?
Geez do not mind the caps...hit the wrong button...

I personally would do this before switching gears in the rear (even though i am shooting myself in the foot for business...lol) Get a 3 speed trans a 350th will bolt pretty close to right in place of the POWER GLIDE. If your wanting a all original car just save the PG for later for resale original parts etc. BUT I guarantee that will bump up first gear and give your car a nice kick in the torque butt. While doing this get at least a 2000 stall torque converter. 2500 will be even better for more burn out fun.

You really need to get in the rear and find out what ratio the car is... The edge of the ring gear will have the ratio / tooth count stamped in (attached example picture) top one is 13 42 (3.23 ratio) next is a 3.42 (12/41 tooth count)

Do get info on the ignition...IF the ignition is points ...please try to upgrade to something better. AN old school guy that knows how to keep up the maintenance of points he could keep it up...but for you ...I would get something much less hands on dial it in and forget it for 50.000 miles deal. :)
A unilite / HEI MSD something electronic type. I personally have a 6AL box and MSD distributor which is a bit much for a driver BUT I will tell you it is superior for starting driving and all around versatility...(might be expensive for the regular guy) 500.00 for the set-up.

Thank you, Jim Mitschke
J D Race
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