318 to 390 hp?
Yes a 390 stroker would def make over 400 h.p. But I think the 390 kits are pricey,more than other small block stroker kits.I could be wrong but I remember looking at them on speedomotives sight a while back.
Maybe things have changed?
Where are you? I have a 360 block with no main caps I could sell ya for $50.