Note the differences in the bolt patter in Dodge power wagon bell-housings , On Left is the  later after 1956 up with a larger center hole  and  On The Right Early 1955  back all WWII & all M37 transmissions. 

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1799592-2 Bell Housing from 1959-60 dodge Truck 318 Poly, 3 speed  , 4 speed np420,

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This is a  Small Block hydraulic clutch type bell housing  use from 1961to 68 in Big Dodge trucks engine 273 ,340, 318 & 360 . . Bolt Patten for Transmission   late NP420 4sp with the v8 input , np435 4sp &  np540 5sp .   Casting p/n , 15" flywheel  with 11" clutch assy

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 Camp Special  Hydraulic Big Block found in
66- 67 -68 , with  383 , bolt Patten for transmission 420,435, 540 , 15" flywheel 11" clutch  casting  p/n - n/a

This is a  Lager Big Block hydraulic clutch type bell housing  use from 1961to 68 in Big Dodge trucks engine 361 & 413 . . Bolt Patten for Transmission   late NP420 4sp with the v8 input , np435 4sp &  np540 5sp .   Casting p/n C93961, 16" flywheel  with 12 or 13" clutch assy

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DODGE TRUCK SMALL BLOCK BELL-HOUSING Casting  #2899163 , 1969 -93  W-D  trucks  318 340  360
made in both steel & aluminum.

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1969-78 Dodge Big Block Truck Bellhousing
383  400  440      casting  # 3497272

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