Hello everyone,

I got a pristine 1978 Mercury Marquis Coupe with the V8 400ci. The car runs beautifully, but as you can imagine the gas mileage is not exactly stellar.
I am planning on using the car regularly, and to avoid to stress the engine too much at highway speed and maybe to save a bit on gas, I was considering swapping the C6 3 speed for a 4 speed auto.
I have researched the matter and I have been told that to use an AOD i would need an adaptor plate that runs about $1K.
Is there any other options that could be considered? I am new to the FLM world. ANy help or advice is welcome thanks!