Flywheel pn 3729004 not available?

[cookeemann]

Searched thoroughly and can't find the answer.

- 66 C10, 3spd, 250 ci with 10 inch clutch
- Original GM flywheel pn 3729004 not available anywhere and mine is cracked to bad to turn
- Can you just upgrade to the 11 inch components...flywheel, clutch and disk since the flywheel is the same diameter (14.10")?
- Anyone who's done this have the part numbers you used?
- Any help greatly appreciated as this is holding up the new engine going in
Thanks

[Palf70Step]

This may help as from what I have seen that is not necessarily the p[art #, but a casting number

Notes from the old corvette board

Yep, from personal experience (NOT hearsay), I can assure everyone that the larger, 14in diameter, 168 teeth flywheel with an 11in clutch WILL FOR A FACT fit in any 55-later iron or alum bell housing with the open bottom.
MOST 55-through mid-60s V8 applications had a 168 teeth flywheel with a bolt pattern that would ONLY accept a 10in clutch. BUT, heavy duty (ie taxi, police, truck, etc) applications had a 168 teeth flywheel with a bolt pattern for an 11in clutch--------------which all fit within the same type bell housing. For example, the same alum bell housing used for 60-62 Vettes was also used up through 63 on hi-perf 348-409 engines in full size pass cars. Even though the Vettes up through 62 had a 168 teeth flywheel with a bolt pattern for a 10in clutch, the vehicles with the 168 teeth flywheel and 11in clutch was still contained in the same style bell housing.
The 60 and 61-62 (63 for 409 cars) Vette alum bell housings had different casting numbers, but they were still PHYSICALLY identical with the single exception of a different size hole for the throwout bearing fork. These alum bell housings were virtually identical to the iron housings that were first introduced on the 1955 V8 engines.
As we speak, I personally have cars (including my 56 Vette) with the open bottom style housings (both alum and iron) and 168 teeth flywheels/11in clutches.

Also

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

This seems to have the most info as far as numbers goes:
http://www.hemmings.com/magazine/hmn...s/3704891.html

Sounds like you should be able to swap it over though.