The Edelbrock Performer DOES have the smaller intake ports. I have 3 of them in my shop. The small block RPM intake has the larger ports to match 340/360 heads.I ran a regular Performer intake on a 360 I had and didn't like the way it ran. Going to a stock 360 spreadbore intake made a big difference. The only reason I can see for running the larger port intake on small port 273/318 heads, would be if you have nothing else. As I stated earlier, the factory made small port spreadbore intakes and used them on both 318 and 360 engines in the 80's. Cab, I think you were referring to the early LD4B(small ports) or the LD340(large ports).