RB Head gasket differences

The block I am prepping to replace my cracked Original has HUGE chamfers. Some will come out with decking, but I will still need to use 4.590 bore head gaskets to keep the fire ring away form the edge.

496" @ 4.360, 10.4:1 compression, Ported Eddie RPM's, little over 600 HP.

Fel-Pro 1105's and 1039's appear to be identical except for the comment about a pre-flattened steel ring, and the obvious dual bolt pattern on the 1039.

What is the difference? I would go Cometic, but nothing is available in-stock on my time frame. I looked at the 8519-PT1's, but they are "only" 4.5" bore.

I assume either of those Fel-Pro's would be fine

I have the same issue with my block. Keeping the head gasket from intruding beyond the clamped surfaces of the head and block on my motor will likely take a custom copper head gasket and a die grinder. The combustion chamber on the head has had the valves unshrouded in the same spot. I may actually have that area welded up and reshaped to better match the bore notches.