[Fast67VelleN2O]

I'll put my worthless 2 cents in here. The runner design tells alot here. Don't pay attention to the 3 hole opening. The runner design is very very close to a 610 intake manifold. The date comes in close to Z development. They did use off the shelf parts for the Z, however, the manifold wasn't there yet. There had to be a missing link between the 490 and the 610 manifold. I think this is it. Remember, in 1967 the 396 069 intake went to a 2 hole opening. In 66 it was still a 3 hole 069 manifold. I can see this 0-117 manifold being the prototype for the 610 based soley on runner design alone.