Ford ,Chevy,exc.Parts in your mopar

I'm one of those with mixed parts in their Mopar. I bought my Duster with a GM 700R4 trans. The person I bought the car from was wanting gas mileage. The best he could do was about 15 mpg. Yea, the cost of the adapter plate and what it took to get the trans to fit and mount to the engine would not have been worth it to me. I would just have left the 727 in it.
There was an episode of Pinks that had a Duster with a Chevy engine in it.