OP
You got the DZ education on muncies . He knows

 

Given the Power Team information shared here, I now wonder how my car was originally ordered/delivered. Could a 350HP car be ordered with 3.36 gearing?

 

You have asked an interesting question. According to the 65 power team chart in an earlier comment, all 65 327/350 cars got a close ratio trans by default and therefore the 3.36 rear was not available. However, the rear in your car certainly appears to be original by its date, and it is marked as a 3.36. Your transmission also appears to be original by its date and vin marking. It is almost certainly a wide ratio transmission.

There are two possibilities. One, your car was originally a 327/300 which had a standard power train of a wide ratio/3.36. Or, two the power train chart published early in the 65 model year did not represent what was being offered later in the year for a May car. In 1966 the 327/350 was offered with either a wide ratio trans with 3.36 as the default rear or a close ratio trans with 3.70 as the default rear. Is your engine also original? Does it still have its original pad stampings?

There is a simple way to determine if your transmission is a wide ratio or close ratio. At a given road speed the rpm will be 48% greater in third gear than in fourth with a wide ratio but only 28% greater with a close ratio. For example, you drive in fourth at 3000 rpm (about 60 mph) and note the speed. Shift to 3rd gear and bring the car to the same road speed. If the tach reads about 4440 rpm (3000x1.48) it is a wide ratio. If the tach reads about 3840 (3000 x 1.28) it is a close ratio. You can run this test at a lower road speed like 2000 rpm but the spread 2960 vs 2560 is less and may be ambiguous if the tach is not accurate.

 

Thanks for the reply! I know the engine is a replacement item from the stamping and casting data - MY67 L79, built in November 66. Unfortunately, there are not any old records of the original order or build for the car. GM sure did us all a disservice by tossing all the old factory records...but it makes for lots of interesting detective work! Once I get out on the road again, I will use your "RPM test" to figure out the transmission configuration. Much appreciated!

 

My 67 was ordered with L79, 3.36 axle, and a close ratio Muncie / 2.20 1st gear. Not the best combination for smooth easy starts, especially on hills.

 

on 1967, GM did include a “ tank sticker”, glued to the top of the fuel tank. This tank sticker will indicate the original options that came on the car.

 

​​​​​FYI, the rpm drop between 1-2 and 2-3 are essentially the same for wide ratio and close ratio versions.

The “Wide” versus “Close” difference is only apparent between 3rd and 4th gear.

 

Easy way to tell if your car has a wide ratio or close ratio box:

In 4th gear, drive with the engine running at exactly 1000 RPM. NOTE VEHICLE SPEED.

Downshift to 1st gear.

Return to the previous vehicle speed. NOTE THE TACHOMETER READING.

If tach sez 2200 RPM, you have a close ratio box. If tach sez 2520 or 2540 RPM you have a wide ratio box.

Q.E.D.

 

Now, just for fun, to torment others who do not know all the variations of a Muncie, aftermarket, offshore gears in various ratios are available for the Muncie.
l have built 3 M22W (wide ratio M22), one for our 70 Chevelle, two for other people.
For owners who have a high geared rear, and an M22 was NOT available, you can have your 2.73-3.08-3.36 rear and an M22.
You get the best of both, stronger gears and the distinctive M22 whine. I'm so vain that I just had to have one and don't have to lie about having an M22.

 

I have been able to determine the rear end ratio in my car is 3.70.

As I have the 327/365 L76 engine with this ratio, I am assuming a close ratio Muncie 4 speed would be the correct transmission for my car...?

 

I believe that would have been a factory recommended choice, but options were available to order.

 

I drove mine with the 3.36 for only a very short time, but did not think it felt lethargic for the couple of brief drives. Perhaps I have a wide ratio (which will be determined soon)? In any event, bBetween rebuilding/restoring the Holley and switching to 3.55 gearing definitely woke up the performance feel of the car though. I did both at the same time, so hard to tell which made the most difference. That's what called the transmission specs into question, as it seems I shift, shift, shift - then I'm quickly in 4th and wishing I had another gear...

 

I understand- that’s why I went to a Tremec 5 spd……. but that’s a whole nother discussion!

 

Yep. I have one in my Superformance Cobra. Makes all the difference...