71 M-22 LS-5 or LS-6?

**Ed Jennings** · November 11, 2002, 10:10 AM

Re: 71 M-22 LS-5 or LS-6?

I owned a 71 LS5 when it was new and it did NOT have a M22. For whatever that's worth.

**Michael Strinich (11202)** · November 11, 2002, 10:18 AM

Re: 71 M-22 LS-5 or LS-6?

In 1976 I purchased a 71 LS-5 convertible that was loaded. It was numbers matching and yes, it did have an M-22. The VIN was on the transmission and it was listed on the tank sticker. This car was a very early build, late 600's in VIN.

I owned this car for over ten years and sold in the mid-late 80's. It still had the original drivetrain.

I may still have a copy of the tank sticker???

**Jim Trekell (22375)** · November 11, 2002, 11:37 AM

Re: 71 M-22 LS-5 or LS-6?

Have you searched in the dash area for a copy of the build sheet. My 68 and 70 had build sheets in this area. Does the code on your transmission confirm the transmission in your 71 is a M22? All 4-speeds in your moded year had drain plugs.

**Chas Kingston** · November 11, 2002, 12:44 PM

Re: 71 M-22 LS-5 or LS-6?

Back in '73 or '74, I had a '71 454/425 w/ M-22 transmission. You can tell that transmision by the straight gears; you can hear the gear whine three blocks away.

I had the devil's own time trying to sell that car. All the gear-heads in Chi-town had 435s or 4¼s, and none wanted a low compression motor. I had plans to upgrade the compression, and had even bought the rods and pistons, when I found that the engine was externally balanced and no one in the area had the capability to do that job in those days.

Finally sold the car for $4400 to some Iowa farm boys.

Wish that I still had that car; would probably be worth a tidy sum, today.

Geezer

**Bernard Sullivan (21116)** · November 11, 2002, 01:00 PM

Re: 71 M-22 LS-5 or LS-6?

The tach redline should be 6500 if it was a LS6 and 5600 if a LS5

**Richard Hayes** · November 11, 2002, 01:14 PM

Re: 71 M-22 LS-5 or LS-6?

Yes, from my understanding it is a M-22. I had it gone through 20 some odd years ago and the guy who worked on it said it was a M-22 w/ a 2.20 first gear. And it whined alot! The vin numbers match( last 5) and the C proceeds (A=M20 , B=M21 , C=M22 from what I have been told) The output yolk is almost as large in diameter as the driveshaft- which is also supossedly a tell tale sign of the M22. The bellhousing (# 3858403) is supposedly for the 10.4 dual disc.
The interior is out of the car and there was no other build sheet to be found.
Any help will be appreciated!!!

**Duke Williams (22045)** · November 11, 2002, 01:21 PM

Re: 71 M-22 LS-5 or LS-6?

M-22 does not have "straight" gears. They are helical (except reverse) as the other Muncies, but the gears have a lower helix angle, which gives them greater torque capacity and also makes them noisier.

Duke

**Richard Hayes** · November 11, 2002, 01:54 PM

Re: 71 M-22 LS-5 or LS-6?

If you are correct then my car is a LS-5. It starts getting orange at 5300 and red at 5600.

Thanks- I guess since the original motor is long gone - and not the really rare LS-6-I'm not quite as bummed!!! Although I have the owner's (that had the original motor swapped) name, address, DOB and SS# from 20+ years ago-just maybe I'll find it!

**Joe Lucia (12484)** · November 11, 2002, 02:49 PM

Re: 71 M-22 LS-5 or LS-6?

Richard-----

A few things:

1) The "C" suffix code for M-22 trans was not part of the VIN derivative; it was part of the transmission production code (the other series of numbers stamped in a slightly larger font style). Your production code has an unusual series of characters; usually the "P" (the ID for the Muncie, IN transmission plant) is the first character in the series. In your case, it's last. In any event, the rest of the production code would indicate that the transmission was built for the 1971 (1) model year on February 22 (B22). The second "B" in the series indicates that it's an M-21.

2) Neither the LS-5 or LS-6 used the GM #3858403 bellhousing. Although all LS-6 with manual trans did use a 10" dual disc clutch, the flywheel was a 14", 168 tooth unit. The LS-5 used an 11" single disc clutch with a 14", 168 tooth flywheel (but, not the same flywheel as used for the dual disc set-up). So, both LS-5 and LS-6 used the GM #3899621 bellhousing designed for 14" flywheels. The only 1971 Corvettes which used the 3858403 bellhousing were the ZR-1s. However, the '403' bellhousing was used in MANY other Chevrolet applications over the years and is quite common. Someone retrofitted it to your car.

**Richard Hayes** · November 11, 2002, 04:14 PM

Re: 71 M-22 LS-5 or LS-6?

hey Joe,

Thanks for the information. After finally figuring out what my car really was-'71 LS-5 w/ M-21 convertible. I am a little relieved realizing it's not that of a rarity, I'll feel more comfortable dropping in a ZZ502 and making it a driver.

**Norris Wallace (6139)** · November 12, 2002, 10:19 AM

Re: 71 M-22 LS-5 or LS-6?

Richard, one other comment that I didn't notice that anyone else mentioned. The later M21's had not only the lower drain plug but the big output shaft as well.

**Joe Lucia (12484)** · November 12, 2002, 12:28 PM

Re: 71 M-22 LS-5 or LS-6?

Norris and Richard-----

Yes, ALL 1971-74 Muncie 4 speed transmissions used the 32 spline output and the same output yoke as 68-77 Corvettes with THM-400.

71 M-22 LS-5 or LS-6?

71 M-22 LS-5 or LS-6?

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