I've got a '68 307 I'm connecting a T5 to. I've already counted splines and test fit everything, It really shouldn't be that bad to put the transmission on by hand...i did a couple test fits with a big buddy of mine while i checked everything. If its not plugging in then there is another problem that could be the one stated by Mike. i really like the T5. you should be happy with it once you get everything plugged in.