Masthead truck/crane

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First time posting. Sirius 21. Masthead rig.

My main halyard block jammed or broke and I need to replace it. However, next year I want to install a spinnaker. I'm new to fixing rigging so I need advice on whether I should look for a masthead truck for my boat - may be hard to impossible to find; are there generic trucks; should I bolt on a crane overtop; or is there some other solution I am missing to having at least the three halyards with the spinnaker halyard above the forestay.

Where would I even begin to look for a truck for my boat or are they some standard size?

Halyards lead outside the mast.

Thanks a million.