'65 flywheel

[Twan B.]

The flywheel on my '65 300 HP does have # 3789733, is this correct for my '65?

Thanks,
Twan
#44079
Dutch chapter

[Wayne M.]

Re: '65 flywheel

The flywheel on my '65 300 HP does have # 3789733, is this correct for my '65 .....

Twan -- casting number for '65 small block manual trans (visible when inspection cover is removed) is 3791021, and if you rotate the flywheel a bit more, you should be able to see the casting date (same format as block date), which should precede the engine assembly date.

[John L.]

Re: '65 flywheel

Twan
Here's a couple of pictures (I'm trying this for the first time) that I just happen to be archiving and thought I would try this picture insert thing when I read your post. The flywheel is from a '65 250 hp April car.

MVC-006S.JPG

MVC-007S.JPG

[Joe L.]

Re: '65 flywheel

The flywheel on my '65 300 HP does have # 3789733, is this correct for my '65?

Thanks,
Twan
#44079
Dutch chapter

Twan-----

I believe the GM casting #3789733 is a 14" flywheel for use with an 11" clutch. NO 1965 Corvette originally used a 14" flywheel and 11" clutch.

Can you confirm the OD of the flywheel and what is the casting number of the BELLHOUSING installed on the car?

[Lynn H.]

Re: '65 flywheel

Twan-----

I believe the GM casting #3789733 is a 14" flywheel for use with an 11" clutch. NO 1965 Corvette originally used a 14" flywheel and 11" clutch.

Can you confirm the OD of the flywheel and what is the casting number of the BELLHOUSING installed on the car?

Joe,
I thought you might see this thread and have some useful information. And I am just asking but, didn't the 65 big blocks with the 3872444 bellhousing come with the larger clutch? Or just the larger bellhousing? Am I reading the book correctly that this 3791021 flywheel, is just the casting number on the flywheel, and the part number is 3973452?
Thanks,
Lynn

[Wayne M.]

Re: '65 flywheel

...... but, didn't the 65 big blocks with the 3872444 bellhousing come with the larger clutch? Or just the larger bellhousing? Am I reading the book correctly that this 3791021 flywheel, is just the casting number on the flywheel, and the part number is 3973452? .....

Lynn -- even the 396 used the 3858403 bellhousing. The pressure plate was the same, big block or small. The clutch cover had a different part # for 396 (versus 327).

The part # on the GM box for the 153-tooth flywheel, cast 3791021, is one digit higher, 3791022.

[Joe L.]

Re: '65 flywheel

Joe,
I thought you might see this thread and have some useful information. And I am just asking but, didn't the 65 big blocks with the 3872444 bellhousing come with the larger clutch? Or just the larger bellhousing? Am I reading the book correctly that this 3791021 flywheel, is just the casting number on the flywheel, and the part number is 3973452?
Thanks,
Lynn

Lynn------


As far as 63-67 Corvettes go, GM #3973452 was a SERVICE flywheel which replaced the original flywheel, GM #3791022, in December, 1971. However, it may have used the original casting number of 3791021.

[Lynn H.]

Re: '65 flywheel

Lynn -- even the 396 used the 3858403 bellhousing. The pressure plate was the same, big block or small. The clutch cover had a different part # for 396 (versus 327).

The part # on the GM box for the 153-tooth flywheel, cast 3791021, is one digit higher, 3791022.

So the 444 bellhousing is 66?? The 3973452 number is one I got from the Sept 75 Chassis and Body Parts Catalog:
GR 0.666 Flywheel w/Ring Gear
63-68 Corvette (283,327) P/N 3973452-solid type (cast 3791021)
Is this a superseded number or something like that??
Thanks,
Lynn

[Lynn H.]

Re: '65 flywheel

Thanks Joe!!
What about the bellhousing, the 444 was NOT used at all in 65? Would that make it 66 only?
Lynn

[Joe L.]

Re: '65 flywheel

So the 444 bellhousing is 66?? The 3973452 number is one I got from the Sept 75 Chassis and Body Parts Catalog:
GR 0.666 Flywheel w/Ring Gear
63-68 Corvette (283,327) P/N 3973452-solid type (cast 3791021)
Is this a superseded number or something like that??
Thanks,
Lynn

Lynn-----


The '444' bellhousing was used only for 1966-E67 Corvettes with big block. It was also used for 1966-E67 Chevelles with big block.

[David L.]

Re: '65 flywheel

The 3872444 bellhousing was used on 1966 & early 1967 Corvettes & Chevelles with the BB engine and was replaced with the 3899621 in Nov. 1966 as per Chevrolet Parts History. I do not know when the change took place on the assembly line.
In this rare case the GM part numbers are the same as the casting numbers.

[David L.]

Re: '65 flywheel

The flywheel on my '65 300 HP does have # 3789733, is this correct for my '65?

Thanks,
Twan
#44079
Dutch chapter

Twan,

The 3789733 flywheel (GM part # 3889694, Gr. 0.666 in the parts catalogs) was used with an 11" clutch (12 5/8" bolt circle). This is the same flywheel in my 1970 Camaro SS350 w/Muncie 4 speed. It was also used on big block cars. What is the date code on your 3789733 flywheel?

Your 65 Corvette w/300 HP should have a flywheel with casting # 3791021 (GM part # 3791022).

Dave

[Joe L.]

Re: '65 flywheel

Twan,

The 3789733 flywheel (GM part # 3889694, Gr. 0.666 in the parts catalogs) was used with an 11" clutch (12 5/8" bolt circle). This is the same flywheel in my 1970 Camaro SS350 w/Muncie 4 speed. It was also used on big block cars. What is the date code on your 3789733 flywheel?

Your 65 Corvette w/300 HP should have a flywheel with casting # 3791021 (GM part # 3791022).

Dave

Dave-----


I believe that the GM casting #3789733 flywheel was also used alternately with the GM casting #3714463 for the GM PART #3758595 flywheel which was used for many 1958-65 Chevrolet applications with 14" flywheel (but NOT 58-62 Corvette 14" applications). I think the 3789733 casting was also used for some truck application flywheels of unknown part number in the 61+ period. So, whether the 3789733 in this case "started life" as a 3758595 or a 3889694 will depend on the casting date. If it's 1966 or later, it is likely a GM #3889694. If it's 1965 or earlier, then it's definitely a 3758595 or some other truck flywheel of unknown part number.

I do not know what the difference was between the 3714463 and 3789733 castings or, for that matter, what the difference was between the 3758595 and 3889694 flywheels. The 3889694 did replace the 3758595 for SERVICE so we know there's rearward compatibility. We don't know if there's forward compatibility for the 3758595 for 3889694 applications, though. Likely there is, but I don't know that.

[Twan B.]

Re: '65 flywheel

Thanks for all the answers,
First of all Joe, It's explicable now to me now i know that my bell house i bought in the past did'nt fit because of the flywheel is 11" (i brought it back so i don't know the # of it) also my bellhouse is "i think" from a '57 because it is always been like this, i believe that earlier Corvettes used a bellhousing that was in two pieces and the lower one is missing on my Corvette (where is the # from the bellhousing located?) the date is J1657.
The flywheel does have 11(2) 9 as date.
Yes.........the previous owner of my Corvette was NOT a Corvette lover but an &*%#$

Twan
#44079
Dutch Chapter

[Joe L.]

Re: '65 flywheel

Thanks for all the answers,
First of all Joe, It's explicable now to me now i know that my bell house i bought in the past did'nt fit because of the flywheel is 11" (i brought it back so i don't know the # of it) also my bellhouse is "i think" from a '57 because it is always been like this, i believe that earlier Corvettes used a bellhousing that was in two pieces and the lower one is missing on my Corvette (where is the # from the bellhousing located?) the date is J1657.
The flywheel does have 11(2) 9 as date.
Yes.........the previous owner of my Corvette was NOT a Corvette lover but an &*%#$

Twan
#44079
Dutch Chapter

Twan------

It sounds like you have a 55-62 style bellhousing (also used on a few passenger cars through 1963). I've never seen one of these installed on 63+ Corvette, but I guess it can be done. To use one of these, though, one also has to use a bellhousing mounted starter. The whole set-up would be very, very incorrect.

To get the car correct, you'll need a GM #3840383 or GM #3858403 bellhousing, a block-mounted starter with an aluminum starter nose (straight across bolt pattern with long and short starter bolts), a GM casting #3791021 flywheel, 10-1/2" pressure plate assembly, and 10-1/2" friction disc. All of these parts are pretty easy to get (here in the USA, anyway) EXCEPT the 3791021 flywheel. That's hard-to-find and, as far as I know, not currently available in reproduction or aftermarket replacement.

You can use a 14" flywheel and 11" clutch if you wish. Although not correct, such a set-up will perform well. Externally, it won't look much different than original PROVIDING that you use a GM #3899621 bellhousing. There's no way I'd continue using the bellhousing you apparently have on the car now. The 3899621 is not difficult to find used (here in the USA) and it's also available in reproduction.