my comments were based on the fact he was offered a 318 short block, which he asked what it was worth. so he did'nt at that point have any motor for his 400hp goal. on that basis a 360 would be more reliable/flexible and easier to build to that hp goal.
as i also said i've had a few 318's, 360's are harder to find here in the uk. they are available to the op so the convenience of his mate's offer seems the only reason to go 318. if i were to build a 318 from scratch here in the uk i'd use a 4" stroker kit to get me a 390.