This video is a about the above entitled description. The GM 270 is 1 & 5/8 of an inch longer than the original Chevrolet 235. The front cross member where the 235 sits must be modified to accept the GM 270.
The modification is well worth the effort in terms of more engine power and the benefit of the C.C.K.W. 5 speed transmission which in this application, 5th. gear is an overdrive ratio of about 30%.