67 flywheel

[Mark G.]

I have my 67 400hp 427 apart and it has a flywheel 3728004. Anyone know what it is from?

[Joe L.]

Re: 67 flywheel

Mark-----

I think the number is actually 3729004. The casting number 3729004 was used for 1963-64 passenger car with 409 and 64-67 6 cylinder trucks with HD clutch. The part number asociated with that application was GM #3739423.

I would not rule out the possibility, though, that the same 3729004 casting MAY have been used for the flywheel originally installed on your car, GM PART #3889694. I can't confirm that, but I think it's very possible. If so, you likely have the original flywheel.

[Tom D.]

Re: 67 flywheel - GM Procedure?

It seems to me that GM might have issued some paperwork allowing for the substitution of what (today) is called an alternate or optional part.

Their Bill of Materials system (PDS, started in late 70s) allowed for a designer to specify such alternates, along with an indication of which is the preferred part.

The system was not as old as the car in question, but the system was designed to suit the situations GM wanted to handle...

T. Dingman
4889

[John H.]

Re: 67 flywheel

3729004 was also the casting number for all '56-'62 flywheels (14", 168 teeth, drilled for the 10.4" clutch).

[Joe L.]

Re: 67 flywheel

John----

Yes, that's correct. I thought that number looked otherwise familiar to me. For some reason, I was thinking that casting number was 3729001, but it was the 3729004. I don't understand, though, how the C1 flywheel could have been used for a C2 application. It may be that the 3729004 casting was used for more finished flywheel part numbers.

[Mark G.]

Re: 67 flywheel

Thanks for the responses. It is indeed a 14" 168 tooth flywheel, and had a 10.4" clutch bolted to it. The 10.4" clutch would suggest to me that it is not the original setup. I havent weighed it, but it is hollowed out on the back side and doesnt feel anywhere near 30 or so pounds.

[Joe L.]

Re: 67 flywheel

Mark-----

In that case, it sounds like it is the C1 set-up that John mentioned. I had no idea that a C1 clutch set-up would work in a C2 bellhousing.