how much all spice to replace 1 1/2 tsp cinnamon

Is this because you're out of cinnamon? I wouldn't sub allspice for cinnamon! I hope you have some other warm spices to use along with the allspice -- like nutmeg, mace, cardamom. For me, allspice, like dried ginger are spices to be used sparingly. They can really take over.

Ok - The I would up the ginger and cloves by 1/4 teaspoon each and add 1/4 teaspoon allspice. Your pumpkin pies will still have a nice spice mix

My recipe calls for:
1 1/2 tsp cinnamon 1/2 tsp each ginger cloves and nutmeg
this makes rwo pies does your answer still apply?

Allspice is kind of a strong flavor. Why not use 1/4 teaspoon allspice and then 1/4 teaspoon each of ginger and nutmeg