There is virtually no difference between the 55-59 V-8 bellhousing and the 63-67 bellhousing with the exception of the casting number. Simply remove the clutch fork which is held on the ball with a spring clip. Either fork will work on either bellhousing. However, the straight fork will not match up with the 56 clutch linkage. You will likely have to take the old engine & trans out and match up the parts you need for the conversion. As stated, if you have the 56 bellhousing - use it.
Also, there is no physical difference between Chevy small block engines. 265,267,283,302,305,307,327,350, & 400 all used the same basic casting and for the most part the external parts are interchangeable.
Fred
