Stock flat top Ford pistons have reliefs machined into the top, they were meant for 1.84 diameter valves thus anything larger might interfere. Even the dished versions had reliefs so it is wise to check for clearance, you will likely have to enlarge the "eyebrows" on the tops but you probably won't have to deepen them with that cam.
You could bolt a head on minus gasket and then put a chunk of clay or plumbers putty on the piston and check for interference, remember to oil the valve head so it won't stick. Clearance should be around 0.050" or more, if not you could "kiss" the valve if the engine valve floats.
Machining is the professional way to enlarge them but a die grinder works just fine too, just do a nice job of it and tape the top of the pistons so no chips get in between the top ring land and bore. I usually tape the entire deck surface with duct tape and then grind through, chips in the water passages are not healthy either. Layout your lines with machinist blueing and then scribe a nice arc into the piston top, be careful with the grinder and go slow. When you hold the grinder approximate the valve angle so the groove is correct. Sounds harder than it really is, you'll get the hang of it after the first relief is done.
Good luck and wear eye protection.
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