I've got a 66 FB that came with a c4 but I'm gonna go with a four speed, sometime in the past someone hung a pedal in it and since it will cost 700 bucks or better to rebuild the c4 and I wanted a stick anyway I'm going with the manual, I know I could upgrade to a five speed but I kinda want to keep it semi-correct anyway. My question is, is there any differences in top loaders? Did they come in different sizes, were small block and big block ones the same and will certain years fit where others won't? What else will I have to look out for in doing the swap? Help is appreciated.