65 wide ratio vs. close ratio

[Donald T.]

I'm trying to get the correct tranny for my 65 L79 with a 3.55 posi. I was under the impression that the engine option determined whether the tranny was a close or wide ratio, and all L79's had the CR. However, I read conflicting information in the archives that stated that the rear end gear determined WR vs. CR, with 3.55 getting the WR and 3.70 and up getting CR. Any thoughts?

Thanks !

[Duke W.]

Re: 65 wide ratio vs. close ratio

For 1965 if you selected L-79 and M-20 from the option sheet you got a CR trans.

Beginning in '65 there were two four-speed options with L-79 - either M-20 WR or M-21 CR.

The above and all the information on base and optional axle ratios for all transmissions is in the NCRS Corvette Specification Guide.

Duke

[Donald T.]

Re: 65 wide ratio vs. close ratio

Thanks Duke. I have the obligatory corvette library, and the reference materials have conflicting information on this topic, which is why I asked the question. The JG and Noland Adams state that the 65 base and L75 were only available with WR, and all others got the CR. Corvette by the Numbers shows all 327 available with either CR or WR for 1965. The AIM only refers to M20 with no mention of CR or WR. The archives have conflicting information as well. I also can't find any restrictions on rear axle ratio for engine option. If Noland and the JG are correct, one could order an L79 with a 3.08 and it could only come with a CR - which doesn't make much sense. Additionally, Noland's survey shows L79's with 3.36 gears, which means it would have to be a CR - which does not seem like a good combination either.

My otherwise numbers matching L79 3.55 posi has a WR tranny that I don't believe came with the car. I want to replace tranny with a correct restamped unit, and I would prefer the WR. However, if I can determine it was never available with the L79, then I will go with the CR.

[Duke W.]

Re: 65 wide ratio vs. close ratio

The JG and Noland are correct. I've found that NCRS publications and Noland have the fewest errors of all the various references, although they are not error free.

In particular the NCRS Spec Guides are excellent! They were obviously very well researched and edited, and I cannot think of any information in them that I believe is in error.

If you ordered a '65 with L-79 and M-20 the standard axle was (non-positraction) 3.70:1. Positraction was a option and so were (positraction only) other axle ratios: 3.55, and 4.11:1. The '66 L-79 powertrain combinations are not the same as '65.

Duke

[Verle R.]

Re: 65 wide ratio vs. close ratio

I presently own a 65 coupe that I ordered in late 64 and took deliver in March of 65. I ordered from the dealer in my home town of West Plains, Mo, then population about 5000. I distinctly remember what options I ordered because I had to take the order book away from the salesman and find the options myself; he didn't know they existed. I ordered L79 with wide ratio Muncie. They were distinct items on the order list as well as the rearend ratio. The order form contained no restrictions on the combination of engine, transmission and rearend I could order. I was interested in certain forms of going fast so a wide ratio and 4.11 positrac was a screamer. Third to fourth was not good but I was usually so far ahead of the other car it didn't make any difference, they had already quit.

Verle

[Donald T.]

Re: 65 wide ratio vs. close ratio

Thanks Duke! That's what I suspected. I just wanted to be sure before replacing the tranny.

[Duke W.]

Re: 65 wide ratio vs. close ratio

There was only one four-speed transmission option in 1965 - M20. If you ordered M20 with L-79 in '65 you got a CR version of M20 only. Standard axle ratio was 3.70 with 3.55 and 4.11 optional.

If you claim it was OE equipped with a WR and 4.11 your are going against all generally acceptable history as stated in the NCRS Spec Guide.

You can easily verify CR vs. WR. Check your speedo reading in third gear at 3000 revs. If fourth gear at the same speed is about 2350 you have a CR. If it's closer to 2000 to 2100 you have a WR.

In 1966 if you ordered M-20, which was wide ratio the standard axle was 3.36 and a 3.55 was available in Positration only. If you ordered M-21 (CR) standard axle was 3.70 with a 4.11 available in Postitraction only.

Duke

[Verle R.]

Re: 65 wide ratio vs. close ratio

Duke,

I don't speak to all other cars, I speak only of the car I bought new and still own. I am not yet so mentally deficient that I don't remember what I ordered and received and well know the difference between a close ratio and wide ratio transmission. When I placed the order I was driving a 55 Chev with a close ratio 4-speed and a 4.56 positrac.

I do remember specific things about ordering the car since I was young and was ordering my first new car; I was excited!

I don't have paper documentation since such things were not important to many of us at that time, only going fast.

Verle

[Donald T.]

Re: 65 wide ratio vs. close ratio

Verle,

Do you recall if any of your original paperwork specifically stated it was a WR? Is it possible that the dealer received your car with a CR despite how it was ordered and the dealer just replaced the gears prior to delivery to make the sale?

Anyone else have a nonstardard combination with a pre '66 car?

Even though it was GM's intent to restrict the usage, I'm wondering if someone ordered a nonstandard combination, would they actually reject the order?

I am completely unfamiliar with the ordering process at that time since I was 11 months old when my car was built

[Verle R.]

Re: 65 wide ratio vs. close ratio

Don,

I don't remember what the paperwork showed, I probably only looked at the car. I seriously doubt the dealer did anything other than normal dealer prep. This was a small dealer in a very small town. When the car showed up I took delivery as soon as I could get it so they really had no time to do a gear change if they wanted to. They stocked no "special performance" parts so they would have had to order any parts like that.

Verle

[Donald T.]

Re: 65 wide ratio vs. close ratio

Thanks Verle. Based on your experience, it seems that it would have been possible to have special ordered a non standard combination. Of course with a sample size of only one, it's hard to tell if this was just an isolated case that "slipped through the cracks", or available to anyone that knew what to order.

I think I am going to stay with the WR. The CR is mostly hype anyway. CR is great if you have a 4.11/4.56 and are only interested in your ET in the quarter. However, the WR is a much better choice for the street. I used to have an L76 with 3.70 posi and CR, and first gear was just too tall. My current L79 with 3.55 posi and non original WR is much better off the line, and who cares if the RPM's drop 1K from 3rd into 4th?

[Jon #40768]

Re: 65 wide ratio vs. close ratio

I have a big block with a 3:55 rear and a cr. This combo is great for city driving as the downshift to second back to third is perfict for corners and smooth as silk from stop signs.
Jon