Whoa, I just gotta say:

Before you spend all the money & time to rebuild a 351M,
make it into a 400M!
If you're rebuilding with new pistons it's almost free - all you lack is the crank. They are not too rare, in fact I have one, too heavy to ship but the extra 50 inches is WORTH it.

I've had both 351M and 400M in my F-150 4x4s. Neither will be a super-stock drag car, but the 351M is kind of a dog - just not enough inches - and the 400M runs pretty good given a chance.

I ran both the PAW 204-214 cam and the PAW 214-224 cam in my 400M (actually 408M at 30-over). Both ran good but the 204-214 kept better low end. Shift at 4800 to 5000.

For intakes I ran both the Weiand and the Edel Performer EGR. The Performer made about 10 less power but 10 more torque and that mattered more to my 5400 lb truck. But either one is good.

I ran 1-3/4 Hedmans but actually the truck manifolds arent too bad for a mild buildup.

With those open-chamber heads, DONT go over 9.0 compression.

On top I ran an autolite 4300 (600cfm) or a Holley 600 or a Holley 3310 (750cfm), they all clocked near identical.

If you do this to a 400M you will get about 320 to 350 horsepower depending on details and a nice truck motor you can LIVE with (the 204-214 cam, or Comp's 206-206 cam is about the same).
Oh, and stay away from the infamous "aluminum oil pump" if you are so unlucky.
Good luck - get yourself a 400 crank!!!!!