I just sold a 4bbl spread bore intake with a 1980 casting date that had small ports. I do not have the casting number, but I remember looking up the numbers and it said 360-318 engines. I too thought that all small block spread bore intakes had large ports, but this is not the case for some early 80's small block engines. I wish I had written down the casting number because I thought it was strange that they used a small port intake on a 360. When I bought the manifold, I did so because I wanted to use it on a 273 I had. I just sold the 273 and intake 3 days ago.