View Full Version : 70 Camaro SS 350 flywheel for 4 speed


DCL70
06-19-2009, 05:02:59 PM
Pictured is a flywheel for an 11" clutch with a casting number "3789733", "GM", "32", and a casting date of "C 20 0" (March 20, 1970) on the back side. I have always assumed it was the correct flywheel for my 70 Camaro SS 350 (w/4 speed) project. I bought the flywheel at a swap meet about 20 years ago. On the front side it also has casting numbers "0" through "9" to form a circle. The 10 numbers are space equally in a 5" dia. circle. I once had another "3789733" flywheel dated "H 1 8" (August 1, 1968) that did NOT have these "0" through "9" casting numbers.

The GM part number in my 1970 Chevrolet parts catalog (effective Oct. 70) for "70 All w/4BC (350)(exc. Sp. H/Per., A.T.)" in Group 0.666 is 3889694 which was replaced by 3998281 in June 1971 as per Chevrolet Parts History. The 3889694 flywheel was also as early as 1966 on the 1966 Chevelle 396 as per my Corvair-Chevy II-Chevelle parts catalog (Jan. 66).

Is there anyone who own an original 70 Camaro SS350 4-speed with a "3789733" flywheel with these "0" through "9" casting numbers and a date code which is correct for their car that can verify my assumption?

It is my understanding that the 1970 Z28 used a "3973456N" flywheel listed as GM # 3973453 in my 1972 Chevrolet parts catalog (Jan. 1972).

DCL70
06-19-2009, 07:27:55 PM
UPDATE:
I just found a flywheel on Ebay (completed auction) with a casting number "3789733", dated "C 31 0" with the "0" to "9" numbers cast on the front in a circle with a GM part number painted on it in yellow paint "3889694". The pictures are excellant on Ebay item # 150349339104. Sometimes Ebay can be wonderful.

M21RSZ28
06-19-2009, 08:03:43 PM
The Three "3789733" Flywheels I Have Do Not Have The “0 Thru 9” Numbers Casted On Them And Are Dated for 1968 1969 and 1970


"3789733" VS "3973456N"


- "3789733" And "3973456N" Are Both 14” Diameter Cast Iron Flywheels With 158 Teeth Used With 11” Clutch
- "3789733" And "3973456N" Both Have The Same Weight Of 28 Lbs.
- "3973456N" “GM 1” And “N” Is Casted On Back
- "3789733" Does Not Have “GM” Or “N” Casted On The Back
- "3789733" Casting Date Of “d20 70”
- "3973456N" Casting Date Of “f10 1” (my 70 Dated “456” Flywheels Are In The Cars)
- "3789733" And "3973456N" Both Have 3 Casting Tabs On Backside
- Alingment Hole For Crankshaft Flange On Back Side Of "3789733" Flywheel Is Not In Line With Any Tabs
- Alingment Hole For Crankshaft Flange On Back Side Of “3973456N” Flywheel Is In Line With One Tab
- Alingment Hole For Crankshaft Flange On The "3789733" Is Larger At 29/64” Diameter
- Alingment Hole For Crankshaft Flange On The "3973456N" Is One Size Smaller At 7/16” Diameter
- The Difference In Sizes For The Alingment Hole Is The Only Difference Between The "3789733" And "3973456N" That I can Find
- Gm Part Number 3889694 With Casting Number "3789733"
- Gm Part Number 3973453 With Casting Number "3973456”
- I Believe The "3789733" And "3973456" Were Casted By Two Different Suppliers

M21RSZ28

"733" FLYWHEEL 29/64” Diameter Alingment Hole
http://i108.photobucket.com/albums/n22/M21RSZ28/NASTY%20Z28/000_1861.jpg
http://i108.photobucket.com/albums/n22/M21RSZ28/NASTY%20Z28/000_1862.jpg

"456" FLYWHEEL 7/16” Diameter Alingment Hole
http://i108.photobucket.com/albums/n22/M21RSZ28/NASTY%20Z28/000_1863.jpg
http://i108.photobucket.com/albums/n22/M21RSZ28/NASTY%20Z28/000_1865.jpg

DCL70
06-19-2009, 10:40:09 PM
M21RSZ28,

My 3789733 flywheel ("C 20 0", "GM", and "32") has a 7/16" alignment hole and it lines up radially with one of the tabs. I tried the dull end of a 7/16" new drill bit and it was a very tight fit. I also tried the dull end of a 29/64" new drill bit and there way no way it would fit. I believe my 733 flywheel was made at a different plant since it has a "GM" and a one-digit year ("0"). Your 733 flywheel has a two-digit year ("70") without the "GM". It is just like the Flint blocks and heads that use a one-digit year casting date while the Tonowanda blocks and heads use a two-digit year. Do you think that a 70 Camaro SS350 (4-spd.) should have a 773 flywheel with a two-digit year since these engines were made in Tonowanda?

M21RSZ28
06-20-2009, 02:09:30 AM
M21RSZ28,
It is just like the Flint blocks and heads that use a one-digit year casting date while the Tonowanda blocks and heads use a two-digit year. Do you think that a 70 Camaro SS350 (4-spd.) should have a 773 flywheel with a two-digit year since these engines were made in Tonowanda?


The L48 350/300 HP engines were also built at the Flint Engine Assembly Plant - I have a block stamped "V0107CRE" for a February built SS 350 Camaro and another engine coded "V1217CNR"

"CNR" is the code for a 1970 Impala with L48 350/300 HP and M38 TH 350 Trans - "V" is the Flint Engine Assembly Plant code The date code of "V1217CNR" for December 17th 1969 for a January or February 1970 Impala

Depending which plant the engine was assembled at would determine which style date code of "0" or "70" was used on a particular flywheel

I would think it is safe to say Flywheels with "0" casting date would be from Flint Engine Plant and Flywheels with "70" casting date would be from Tonawanda Engine Assembly Plant

M21RSZ28

DCL70
06-20-2009, 10:42:39 AM
M21RSZ28,

Do your 1970 L48 Flint blocks have a 3970014 or 3970010 casting number?

I have only seen the 3970014 blocks on the 1970 L48 engines (maybe 5 or 6 in the last 19 years). I purchased a std. bore 1970 L48 3970014 Tonowanda block dated sometime in May 1970 in Carlisle, PA, a couple of years ago for $200 but it dooes not have the "CNJ" code that I really want. It has a "CRE" code, I believe, but it does have a 1970 Camaro partial VIN ("N" for Norwood) stamped in the vicinity of the oil filter.