Mix yolks with heavy cream in a medium sized bowl really well.
Add sugar, cornstarch, milk and vanilla. Mix well.
Pour into a medium sized pan and heat on medium on stovetop, whisking constantly.
Cook/stir until mixture boils. Allow to boil 1 minute.
Remove from heat.
Stir in chocolate.
Stir in pecans and coconut. Mix well, getting the sides and bottom of the pan completely mixed. It'll be thick like pudding.
Pour into pre-baked and cooled pie shell.
Cover with wrap, pressing wrap onto filling to avoid it getting a skin. Refrigerate.
Add heavy cream to mixing bowl fitted with the whisk. Mix on medium until cream starts to thicken.
Slowly, as mixer is running, add sugar to cream. Continue to mix until cream thickens to stiff peaks.
Remove bowl from mixer and fold Hershey's syrup.
Fold in toasted pecans and coconut just until mixed in. Don't over fold and deflate your cream.
Remove pie from refrigerator and top with whipped cream.
Return to refrigerator until ready to serve.