the I6 engine change was 63 and up. 1962 used the 235 and 261; also used into 63 in some models
in the 1968 trucks and up the frt input brg retainer was enlarged which resulted in a larger dia bore in the bell housing
ron

http://s908.beta.photobucket.com/user/padresag/library/turned%20works
http://s908.beta.photobucket.com/user/padresag/library/furniture
and a little history of where I come from
http://forum.woodenboat.com/showthread.php?156542-old-boatshop-in-Steveston