Years ago, I bought a 1979 or 1980 full size Bronco that had a 351M in it. It was totally gutless so some work had to be done to it, even though it was virtually brand new at the time.
I changed the cam, replaced the intake with an aluminium one, and put on a 600 cfm Holley. I ripped off the single exhaust and had it replaced with a larger diameter dual system.
It then became a totally different truck, very powerful but quite thirsty.
Wayne