The casting date on my manifold was 3-26-81. Casting # 4173915. I was replying to Gtxxjon who stated that they never made a small port 4bbl intake for LA 318. I went through this crap right here on this forum 3 years ago trying to figure out what I had. I had never seen a small port spread bore intake before, so I looked up the casting number info and it clearly stated that the intake in question was used on 360's from 78-80 and 318's from 78-83. I had always thought that big port intakes were used on Lil Reds and E58 engines.