3704923 55-64 Chevy Engine 2 Piece Underpan
General Motors Part Number 3704923 Underpan
The Chevrolet and GMC part number 3704923 is
the lower cover or pan of the two piece clutch
bell housing cover.
Reproduction Car Set
The Part # 3704923 is the cover at the top in
picture above. The "923" fits both early car and
truck bellhousings.
Outside
This is the outside of a new GM part. The paint is
shinier than the aftermarket part.
Inside
In this view you can see the drain hole at the bottom
and get a sense of the depth needed to inclose the
flywheel and clutch assembly.
Part #3704923
The example I have has the part number sticker
the inside.
On "553"
In this picture I have a reproduction pan mounted
on a part # 3779533 aluminum bellhousing. This
is a "true" inspection plate as it can be removed
by loosening four (4) bolts and removing one (1).
I have personally tried this cover on the following bellhousings. the lower cover or pan of the two piece clutch
bell housing cover.
Reproduction Car Set
The Part # 3704923 is the cover at the top in
picture above. The "923" fits both early car and
truck bellhousings.
Outside
This is the outside of a new GM part. The paint is
shinier than the aftermarket part.
Inside
In this view you can see the drain hole at the bottom
and get a sense of the depth needed to inclose the
flywheel and clutch assembly.
Part #3704923
The example I have has the part number sticker
the inside.
On "553"
In this picture I have a reproduction pan mounted
on a part # 3779533 aluminum bellhousing. This
is a "true" inspection plate as it can be removed
by loosening four (4) bolts and removing one (1).
3704922
3779553
Clutch cover applications should be used as a guide to the type of bellhousing used originally used on a vehicle.
Covers should be bought to fit the bellhousing you have.
Applications
3704923
0.679 UNDERPAN, Clutch flywheel (15 1/2" O.L.) (Note 1)
55-62 Pass., Corvette (8 cyl.) (exc. A.T.) (Chevy parts books)
63 Pass. (409) (Chevy parts books)
64 Taxi (230)(2nd Design) (Chevy parts books)
Note 1: Has two indented throughs on surface, trim excess metal to fit as necessary.
Disclaimer:
Most parts that I describe and picture have identification on or with them, others I can identify from other sources and deduction (educated guess).
Factory correct applications are your responsibility. GM made part and part # changes with no rhyme but a reason (no production interruptions at any cost).
Applications are for replacement parts that were available at the time of parts book printing, and when possible model specific assembly manuals.
My observations come from the parts I have in my collection or other reliable sources your parts may differ.
If Factory correctness is your goal, do more research, join car clubs,
forums and buy an assembly manual if one is available for your Project Car (you wont be sorry).
This is a fun and interesting part of the hobby!
