Why do you think a 318 will fall short ?
318 340 350 360 etc.. are an engines static size non running. Just a measure of all the bores add together. But a running engine is dynamic in size depends on rpm.
Well assume all these engine similar in friction efficiency and VE.
That 350 peaks at 5000 rpm so 350 x 5000 equals 1,750,000. An engine only has a intake stroke every other rotation. So you got to divide by 2. Which equals 875,000 cubic inches per minute. Thats the real size here. Now thats a rather large and useless number. So turn it into cubic feet per minute or cfm. So you'd divide by 1728 to get the number or divide the original 1,750,000 by 3456 for simplicity sake which we know as the what people try to use as the carb formula.
Which would be 350 x 5000 / 3456 = 506 cfm. So that engine pulls about 506 cubic feet per minute depending on VE. So since these engine are similar in efficiency it takes about 506 cfm to make 342 hp. A 318 at 5500 rpm would pull 506 cfm. And same with 340 @ 5147 rpm and 360 @ 4867 rpm. At these rpms these 4 engines are the same size. Same potential.
