340 intake on 318
What I like about port matching is the quality of the air and fuel going into the head improves. There’s not a lot to be gained HP wise on a low level power output engine. The port matching pays better dividends on the high end high rpm builds. While not a tremendous gain there ether, I figure if you already have the heads off to port you might as well grab everything you can instead of leaving it on the table.
The above 2-8 cfm loss is port dependent FWIW & good to know.