70 positraction question
Thread Starter
Melting Slicks
Joined: Dec 2003
Posts: 2,487
Likes: 1
From: Sydney
70 positraction question
I know Positration was included in the Base price of 70 vettes...so does that mean that all 70 vettes had positraction? or was there a delete option? and if there was a delete option, does anyone know how many chose not to have positraction?
Was there a standard ratio?
(my bf and I just went and checked the numbers on our diff, and when we looked at the prefix it suggested we didn't have positration..and we were shocked! -but we didn't see the code clearly enough...and we are too stressed to go jack the car up and check if both wheels turn to see if it has positration - oh and its too cold - might try in the morning).
Thanks for your help.
Was there a standard ratio?
(my bf and I just went and checked the numbers on our diff, and when we looked at the prefix it suggested we didn't have positration..and we were shocked! -but we didn't see the code clearly enough...and we are too stressed to go jack the car up and check if both wheels turn to see if it has positration - oh and its too cold - might try in the morning).
Thanks for your help.
Pro
Joined: Mar 2004
Posts: 640
Likes: 1
From: Mertztown Pa
Thats not true. A 3.36 in a 70 was the performance axel ratio. I have it in mine. I also have the positraction warning sticker in the jack box. Also, when the car is lifted both wheels spin in the same direction.
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
According to NCRS spec. guide, the following codes for 1970, and late 69, were standard, (not posi) : CAK, CAL, CAN, CAP, CAS, CAV, CAW, CLR...These include ratios: 3.08, 3.36, 3.55, 3.70, 4.11......
Thread Starter
Melting Slicks
Joined: Dec 2003
Posts: 2,487
Likes: 1
From: Sydney
Originally Posted by big_G
According to NCRS spec. guide, the following codes for 1970, and late 69, were standard, (not posi) : CAK, CAL, CAN, CAP, CAS, CAV, CAW, CLR...These include ratios: 3.08, 3.36, 3.55, 3.70, 4.11......
So thats why Im asking....Positraction became standard (with the base model) in 1970....but if there are codes for standard (not positraction) diffs then does that mean there was a delete option or something? Im confused
(I think I need to go to bed now...
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Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
The codes I listed shows that some diffs. may be non-posi......Just read the 3 letter code on your diff., and if it has not been gone into, then you now know what you have is original....posi or standard...NCRS agrees that they SHOULD all be Posi, but documentation shows a conflict with GM...
Drifting
Joined: Nov 2001
Posts: 1,469
Likes: 6
From: 68 427 4.11s Roadster
Even if it was a delete option I would doubt it would ever get used.
Who would delete posi to save $50 bucks?
I'm wondering how rare base corvettes are in any year. You know, no options at all.
Who would delete posi to save $50 bucks?
I'm wondering how rare base corvettes are in any year. You know, no options at all.
Thread Starter
Melting Slicks
Joined: Dec 2003
Posts: 2,487
Likes: 1
From: Sydney
Originally Posted by big_G
The codes I listed shows that some diffs. may be non-posi......Just read the 3 letter code on your diff., and if it has not been gone into, then you now know what you have is original....posi or standard...NCRS agrees that they SHOULD all be Posi, but documentation shows a conflict with GM...
I am still confused.
Ofcourse, I will have a look at my vette today...but I am interested as to this conflicting documentation and that all 70's came with positraction as standard (well all vettes from 70 onwards - and basically 69 - as nearly all 69 vettes had the positraction option).
Is it as Z-man said? That the word 'standard' in the documentation refers to standard ratios (as opposed to the opptional ratios)?
Now that starts to make sense...
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
The NCRS numbers manual shows 2 letter codes for each axle ratio...1 for posi, 1 for standard...except the 4.56 units..I believe the conflict is that GM issued the 3 letter codes for non-posi units for 1970, but cannot be confirmed to be actually put into service...
Last edited by big_G; Aug 10, 2005 at 11:22 PM.
Thread Starter
Melting Slicks
Joined: Dec 2003
Posts: 2,487
Likes: 1
From: Sydney
Originally Posted by gtr1999
light up the tires a take a look behind 
my vette isn't running properly....its bloody hesitating on acceleration at low rpm...and if you put your foot down a bit it stalls.
(its an auto).
I thought maybe it was the accererator pump (cause it had been sitting for 4 months) but now Im thinking ignition system - Spark Plugs is the first thing Im going to check/change. there is a noticable difference in the feel if you put your hand at the exit of one exhaust pipe compared to the other ...so that Im hoping is spark plugs ... (or leads/wires)
...spark plugs are not that easy to change on these cars are they!! (I got a shock when I had a look the first time)
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
The final answer:
I was wrong!! :o (A first...
)
Check this out, from the Z-man files...
I thought I had read somewhere that all '70s were posies. Here's what mine looks like - 2CAM 3 26 70 W. That's the 3.36:1, March 26, 1970 Warren - positraction. That's about a month before the car assembly date.
I was wrong!! :o (A first...
)Check this out, from the Z-man files...
I thought I had read somewhere that all '70s were posies. Here's what mine looks like - 2CAM 3 26 70 W. That's the 3.36:1, March 26, 1970 Warren - positraction. That's about a month before the car assembly date.
Last edited by Z-man; Aug 11, 2005 at 02:02 AM.
Drifting
Joined: Nov 2001
Posts: 1,469
Likes: 6
From: 68 427 4.11s Roadster
Take into a parking lot or some place with plenty of room Floor it in a turn. Like your turing onto a side street. It will break the wheels loose. just straighten the wheels and look at the marks.
Thread Starter
Melting Slicks
Joined: Dec 2003
Posts: 2,487
Likes: 1
From: Sydney
Originally Posted by Techno
Take into a parking lot or some place with plenty of room Floor it in a turn. Like your turing onto a side street. It will break the wheels loose. just straighten the wheels and look at the marks.
I changed the spark plugs last night
....what a bloody nighmare they are to change! and so my bf and I after perservering were getting excited to test it out....and it was way worse! 
I really can't handle this. I was so excited getting my vette - the inspection said it drove well ...so I wonder if the inspection place were being helpful to the seller! (but I wouldn't have thought so). Im pissed off
We might be taking it to a mechanic.....
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
Since it was such a long journey, there could have been some things go wrong during the trip. Hesitation could be a number of things. Is the accelerator pump on the carb working properly - i.e. when you open the throttle, do you see a good sized shot of gas going in? Are all the vacuum lines hooked up an tight? No leaks around the carb - is it good and snug?
Good luck - we'll get you going!
Good luck - we'll get you going!
