5.9 magnum cam in a LA318(roller)

I bought an 86 Ram D150 a few weeks ago. It has a 318 roller/727 and 9.25 (sure grip) rear with 3.23 gears. I'm wanting to build it for low end torque and fuel economy. Plans are to use an Eddy Streetmaster intake (already have) and spreadbore carb. Also I'll be using early Magnum exhaust manifolds. I have a 5.9 cam from a 95 ram 1500. Would there be any benefit to this cam swap or would I be further ahead to buy a new camshaft? Thoughts/opinions are appreciated