Flywheel Identification

[Chuck D.]

I'm going thru a my 62 340 hp I purchased a few years ago. I again need help identifying if my flywheel is original or correct for a 1962 car. The numbers on the flywheel are 3714463 (could the 63 be the year?) and 45 degrees from this number is 980. I sure appreciate the help. Thanks again - Chuck (58064)

[David L.]

Re: Flywheel Identification

Chuck,

My research shows that a flywheel with a "3714463" casting number is for a 1955 (1st Design), GM # 3714462 in Gr. 0.666.
I also believe that the flywheel with casting # "3714463" is also GM part # 3758595 and GM part # 3789731.

What is the casting date?

Chevrolet Parts history (service parts):
3714462 to 3758595 in Apr. 1960 to 3889694 in Dec. 1966 to 3998281 in June 1971 to 3988759 to 3991469

3789731 to 3758595 in Jan. 1965

These are GM part number, not casting numbers.

The 1960-1962 flywheel is casting # "3729004" (GM part # 3739423 in Gr. 0.666)
3739423 to 3986390 in Dec. 1971

The 1956-1959 flywheel is also casting # "3729004" (GM # 3729003 in Gr. 0.666)
3729003 to 3739423 in Apr. 1960

Dave

[Joe R.]

Re: Flywheel Identification

I'm going thru a my 62 340 hp I purchased a few years ago. I again need help identifying if my flywheel is original or correct for a 1962 car. The numbers on the flywheel are 3714463 (could the 63 be the year?) and 45 degrees from this number is 980. I sure appreciate the help. Thanks again - Chuck (58064)

Chuck,

The 63 just happens to be the last digits of the part number or casting number. There is no relation to the year of the car.

Joe

[Chuck D.]

Re: Flywheel Identification

Dave,
I probably should have asked this question before I ordered my new clutch assembly earlier today. I'm confused which is not difficult for me. If the number 3714463 is a part number and the numbers you showed for the 1960-1962 part history run sequentially could one assume my flywheel was for this car?? The only other number I can find is 980 1. The 980 was between two small bumps with the 1 after the last bump. Where would I find the casting date?? Thanks Dave. Sure hope the bolt holes on my new pressure plate line up with those on the flywheel!!

[David L.]

Re: Flywheel Identification

Dave,
I probably should have asked this question before I ordered my new clutch assembly earlier today. I'm confused which is not difficult for me. If the number 3714463 is a part number and the numbers you showed for the 1960-1962 part history run sequentially could one assume my flywheel was for this car?? The only other number I can find is 980 1. The 980 was between two small bumps with the 1 after the last bump. Where would I find the casting date?? Thanks Dave. Sure hope the bolt holes on my new pressure plate line up with those on the flywheel!!

Chuck,

The 3714453 number is NOT a part number, it is a CASTING NUMBER. Apparently the same casting number was used on flywheels with GM part numbers 3714452, 3758595, and 3789731.

The casting date is on the same side as the casting number. The casting date usually starts with a letter for the month ("A" = January, "B" = February,..........., L = December) with the numbers being the day of the month and the year. Casting digits are sometimes hard to decipher. Sometimes a "G" looks like a "C" and a "6" looks like an "8". The "980" is not typical of a casting date. Could it actually be "B80"?

Dave

[Joe L.]

Re: Flywheel Identification

Dave,
I probably should have asked this question before I ordered my new clutch assembly earlier today. I'm confused which is not difficult for me. If the number 3714463 is a part number and the numbers you showed for the 1960-1962 part history run sequentially could one assume my flywheel was for this car?? The only other number I can find is 980 1. The 980 was between two small bumps with the 1 after the last bump. Where would I find the casting date?? Thanks Dave. Sure hope the bolt holes on my new pressure plate line up with those on the flywheel!!

Chuck------


I'm not sure what you mean by "run sequentially" or "assume my flywheel is for this car". If by the latter you mean assume that the flywheel is ORIGINAL to this car, I expect it is not. But, I consider it possible even though the casting number doesn't appear right for a 1962.

The casting date should appear as an alpha-numeric series of characters. The first character should be an alpha-character (i.e. A through M). This should be followed by 2 or 3 digits.

[Chuck D.]

Re: Flywheel Identification

Dave,
Took another look and I was looking upside down. The casting date when looking right side up appears to be G86 - soooo if I understand - the G=July, the 8=the 8th. of July and the 6 I'm assuming would = 1956??? I see the casting number = several part numbers??? So, is it possible those flywheels with a casting number of 3714463 fit several different years (like 1956??) I'm convinced it is not original to the 1962. Your a very patience man. Thanks once again.
Chuck (58064)

[Joe L.]

Re: Flywheel Identification

So, is it possible those flywheels with a casting number of 3714463 fit several different years (like 1956??)

Chuck------


VERY possible.

[David L.]

Re: Flywheel Identification

Chuck,

My 1963 Chevrolet Parts Catalog (Oct. 1962) lists GM part # 3739423 as the flywheel (w/ring gear) for 55-62 CORVETTE (8 cyl.)(2nd design)(exc. P.G.) & other models as well with the following description:
w/10" coil and diaphragm spring clutch (11 5/8" bolt circle)(cast 3729004)

GM # 3758595 is listed as the flywheel for the 55 CORVETTE (8 cyl.)(1st design)(exc. P.G.) & other models as well with the following description:
w/11" coil spring clutch (12 5/8" bolt circle) (cast 3714463)

What size clutch did you order........10" or 11"?

Dave.

[Chuck D.]

Re: Flywheel Identification

Dave,

I bought the 10" (only one offered by Paragon for 62) eventhough I removed an 11". Obviously wasn't thinking, anyone with any smarts would have known better. My bolt circle measures 12 5/8". Lessons learned.

Chuck

[Joe L.]

Re: Flywheel Identification

Dave,

I bought the 10" (only one offered by Paragon for 62) eventhough I removed an 11". Obviously wasn't thinking, anyone with any smarts would have known better. My bolt circle measures 12 5/8". Lessons learned.

Chuck

Chuck------

All C1 Corvettes used a 10" clutch EXCEPT early 1955. Unfortunately, what you have is the early 1955 flywheel which, in turn, requires the 11" clutch. I HIGHLY doubt the flywheel you have is dual drilled for both size clutches. However, if you had the the latest supercessive part numbered flywheel, GM #3991469 and still available to this day from GM, that flywheel is dual-drilled to work with both size clutches.

[Chuck D.]

Re: Flywheel Identification

Joe, Dave,

Thanks once again!! MY plan - By the time I resurfaced my flywheel, returned the new 10", hunted and ordered one to fit my flywheel would go a long way towards discounting the cost of a new one. I'm going to followup with your very much appreciated info (have no idea of cost for new one) and will get back with ya'll. Thanks again.

Chuck (58064)

[Joe L.]

Re: Flywheel Identification

Joe, Dave,

Thanks once again!! MY plan - By the time I resurfaced my flywheel, returned the new 10", hunted and ordered one to fit my flywheel would go a long way towards discounting the cost of a new one. I'm going to followup with your very much appreciated info (have no idea of cost for new one) and will get back with ya'll. Thanks again.

Chuck (58064)

Chuck------

Personally, I do not like using a re-surfaced flywheel. Re-surfacing reduces the strength of the flywheel. Also, this flywheel you have has likely already been re-surfaced at least once.

As far as the 3991469 goes, it's dual drilled for both the 10.4" and 11" clutches. If the clutch you have ordered is either of those, this flywheel will work. However, if it's a true 10" clutch, as originally used for all 57-62 Corvettes, I don't think it will work. In fact, I don't know of a replacement flywheel that will work with that clutch. That original clutch was a coil spring type clutch (aka "Borg and Beck" style) and I don't even recommend that those be used.

The 3991469 is the current replacement for the flywheel you have. However, that assumes that an 11" clutch is used. The 3991469 is not a replacement for 1957-62 Corvettes with 10" coil spring clutch.

[Chuck D.]

Re: Flywheel Identification

Joe,

I agree re: re-surfaceing. After a good cleaning I'm not sure that I dont't see some, what appear to be hair line cracks. I found a dealer out of state through our local dealer that has one in stock. I plan on calling them and get measurements on Monday. My new clutch ass'y is due here on Tuesday and then I can check what will or won't work. The number Dave provide is no longer available. After-market is always an alternative. I think my preference is to have a little more clutch. Shame on me once but hopefully not twice. Keep me honest Joe.

[Joe L.]

Re: Flywheel Identification

Joe,

I agree re: re-surfaceing. After a good cleaning I'm not sure that I dont't see some, what appear to be hair line cracks. I found a dealer out of state through our local dealer that has one in stock. I plan on calling them and get measurements on Monday. My new clutch ass'y is due here on Tuesday and then I can check what will or won't work. The number Dave provide is no longer available. After-market is always an alternative. I think my preference is to have a little more clutch. Shame on me once but hopefully not twice. Keep me honest Joe.

Chuck-------



There are definitely aftermarket equivalents of the GM #3991469 and they cost quite a bit less. Most likely they'll be of Chinese manufacture. Of course, one might even find that the GM #3991469 is of Chinese manufacture by now. The important thing is that whatever flywheel is used that it's cast of NODULAR iron and not gray iron.