Roll pastry dough to fit 9-inch pie plate. Fit into pan; crimp edges. Refrigerate while preparing filling. Heat oven to 300 degrees.
Put sugar in heavy saucepan. Cook, stirring frequently, over medium heat, until sugar melts and turns medium-brown, about 10 minutes. Add corn syrup; mixture will solidify briefly but keep stirring until it melts and becomes smooth, 5 to 7 minutes. Mix in rum and butter; cook 1 minute. Remove from heat; let cool 2 to 3 minutes.
Mix eggs, vanilla and salt in large bowl. Slowly whisk in hot syrup mixture. Combine pumpkin, cinnamon, cloves and nutmeg in medium bowl. Add 11/4 cups of the syrup mixture to pumpkin mixture. Pour into pie shell. Arrange nuts over top; drizzle remaining syrup mixture over pecans.
Bake until filling is set and knife inserted in center comes out clean, 55 to 65 minutes. Cool on wire rack. Serve with sweetened whipped cream.