61 Chevy Bellhousing
1961 Chevrolet Passenger Car Bellhousing Assembly

3704923
0.679 UNDERPAN, Clutch (15 1/2 " O.L.)
61 Pass. (8 cyl.) (exc. A.T.) (Chevy Parts Books)
(My part number 279 and 277)

3734908
0.679 EXTENSION, Clutch Housing Note 2
61 Pass. (8 cyl.) (exc.409) (Chevy Parts Books)
Note 2 Trim excess metal to fit as necessary.
(My part numbers 278 and 277 )

3817006 (5)
6.79 BOLT, w/washer, under pan and extension attach
61 Pass.(8 cyl.) (Chevy Parts Books)
(My part numbers 281 and 277 )
3785643
0.683 HOUSING, Clutch (Ident. No 3741401 or 3779551)
61 Pass. (8 cyl.) (exc. Sp. H/Per.) (Chevy Parts Books)

3785644
0.683 HOUSING, Clutch (Aluminum) (Ident. No. 3779553)
61 Pass. (409) (Chevy Parts Books)

3729000
0.796 STUD, Clutch Fork (13/16"-16 stud w/21/32" dia. ball)
61 Pass. (348) (Chevy Parts Books)
61 Pass. (283) (2nd design) (Chevy Parts Books)
(My part number 174)

3781385
0.797 BOOT, Clutch Fork (black rubber)
61 Pass. (Chevy Parts Books)
(My part number 351)
3704923
0.679 UNDERPAN, Clutch (15 1/2 " O.L.)
61 Pass. (8 cyl.) (exc. A.T.) (Chevy Parts Books)
(My part number 279 and 277)
3734908
0.679 EXTENSION, Clutch Housing Note 2
61 Pass. (8 cyl.) (exc.409) (Chevy Parts Books)
Note 2 Trim excess metal to fit as necessary.
(My part numbers 278 and 277 )
3817006 (5)
6.79 BOLT, w/washer, under pan and extension attach
61 Pass.(8 cyl.) (Chevy Parts Books)
(My part numbers 281 and 277 )
3785643
0.683 HOUSING, Clutch (Ident. No 3741401 or 3779551)
61 Pass. (8 cyl.) (exc. Sp. H/Per.) (Chevy Parts Books)
3785644
0.683 HOUSING, Clutch (Aluminum) (Ident. No. 3779553)
61 Pass. (409) (Chevy Parts Books)
3729000
0.796 STUD, Clutch Fork (13/16"-16 stud w/21/32" dia. ball)
61 Pass. (348) (Chevy Parts Books)
61 Pass. (283) (2nd design) (Chevy Parts Books)
(My part number 174)
3781385
0.797 BOOT, Clutch Fork (black rubber)
61 Pass. (Chevy Parts Books)
(My part number 351)
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!