ICON 9976 with Magnum Heads?
Do you already have those pistons? If so, can you verify the compression height on them?
That link says they are 360 pistons with 1.675 compression height, which sounds right, but then it says it’s for a 3.310 stroke.
Looking theses up on UEM’s website it says to call them for specs and availability.
Edit
Oops; rumblefish360 already got these questions in while I was logging and typing. Sorry.