1966 427 390hp New GM flywheel

[Hal J.]

1st, I would like to confirm more that the flywheel is still not judged by NCRS??

If true, I am trying to find if there is a new or current replacement GM part number for a 1966 427-390hp flywheel. Only thing I have been able to confirm with my local Chevy parts dept. is that GM does offer 14085720 as a new replacement for a 65 396 flywheel number 3791021. Appreciate any help.
Hal James #10081

[Jack H.]

Re: 1966 427 390hp New GM flywheel

The flywheel isn't Flight judged as that would require major disassembly to gain visible access....

[Hal J.]

Re: 1966 427 390hp New GM flywheel

Thanks. That was also my understanding. Just wanted to hear it again before I changed to a newer/different flywheel.

[Bill Stephenson]

Re: 1966 427 390hp New GM flywheel

Hal,

-------Dont know part numbers for flywheel you need, but you certainly dont need a 396 flywheel as it isnt the same diameter as the 427/390 flywheel or the same weight. You would have to change the clutch, bellhousing, starter snout, fork, etc. to use a 10 1/2 inch clutch. You need an 11 inch flywheel.
-------With that said if you were to change to a 396 set-up with that light flywheel you would like the driveability. Did many of these switchs back in the day and really liked the outcome. Engine revs quicker..........Bill S

[Hal J.]

Re: 1966 427 390hp New GM flywheel

I am staying with 11 inch flywheel, et al. Just trying to find if a new part is available from GM vs after market.

But, a really neat idea... especially with your confirmation of the postive result.

[John M.]

Re: 1966 427 390hp New GM flywheel

Hal, I bought a replacement from GMpartsdirect.com a couple of years ago for a 67 L68, which may be the same one you need. I don't have the P/N

[Hal J.]

Re: THANKS FOR THE INFO *NM* *NM*

[Joe L.]

Re: 1966 427 390hp New GM flywheel

Hal-----

First of all, the 1965 Corvette with L-78 did NOT use the GM #3791021 casting flywheel. The 3791021 was a standard weight, 12-3/4" flywheel used for 1963-68 Corvettes with small blocks. The 12-3/4" L-78 flywheel was a "lightweight" casting and of GM CASTING #3856579. It is currently known as GM PART #14085720. That's NOT a correct part for a 1966 L-36, though.

You require flywheel GM PART #3991469. This flywheel will SERVICE your application perfectly and it's still available from GM. You can also find equivalent aftermarket flywheels by cross-referencing to this number.

[Hal J.]

More Thank You's

Thank you Mr. Lucia. Thank you all for your help. I have been digging for several weeks in my little library of vette stuff and on the internet most nights. This was solved in 1 day here!! This is an amazing group. Thanks again.

Hal James #10081