340 intake on a 318?
A big port intake on a small port head is a mismatch in my book. The first factory LA 318 4bbl's started in 1978. By then you had lots of smog equipment, different castings, but still, ports that matched. Mild cams, lean burn, thermoquads, mild compression ratios and cams, restrictive exhausts, etc. Totally different animals. Some combos work fine, some don't.