Personally, I would dump the chevy and go mopar all of the way. In my opinion, you are ruining a dart by using a chevy engine and tranny. You can run your VIN number on some different mopar websites to see what engine came in your car. It could have been a 6 cyl, a small 318 v8, a 440, or even (but I doubt) a hemi. Darts came with all of these engines and more depending on the year and model. You can find a good 318 and tranny for just a little money. That would be my suggestion.