Funny, I actually did something similar years ago because I was coming from a big block build that didn't pan out and I needed a new trans for my 318/904 combo. I pulled my 904 and put in a used 727 with the converter that I had already purchased for the big block (I was pinching penny's at the time and didn't know better). Didn't realize I would need a new drive shaft...Now, 25+ years later I still run a 727 because I have too much invested in it, and I don't want to drop a pile-O-money to convert back to a 904.