I checked out the color on the block of the 100-4 last night. Healey green is close, but not quite. It seems to be a little darker than the detroit des. alpine green. Side by side, its pretty noticeable. Looking at each one at a time, not so much.
Bear in mind I'm comparing 55 year old paint on an engine that has sat my whole life, to new paint I sprayed out of a can onto a peice of wood. So, take it for what its worth.