65 barracuda headers

4323345 cop heads are 360 castings. 75cc open chamber 1.78 or 1.88 intakes (conflicting data) but the 318 never came with 4bbl heads, they just used the 360s on the limited 318/4 apps. Id try magnum logs...see if they fit. They flow pretty darn good for $50 a set, almost good 68 340 log numbers.
All the ones I had were 1.88" and the ports were sort of in between the older 273/318 size and the 340/360 size. Depending on both intake and exhaust manifolds, you sometimes had to do a bit of port matching. The intake valves are a bit shrouded on a std. bore 273.