Power loss. 318 Vs 340 manifolds

One of the Mopar mags did a test on a 300 HP crate 360 starting with 318 manifolds all the way up to TTI headers. I think the spread was like 28 HP. If I remember correctly the hp manifolds were about 11 hp better then 318 and 7 betther then basic 360 logs. Will try to find it and link it here.