Daily Driver Engine 318 vs 360, what one?

Can't base the idle on displacement, that all has to do with proper cam selection. 425 horse is not something that is achieveable with a couple bolt ons. There are several other factors as far as tranny selection stall rear gears etc.. A 318 at 425 horse is going to take some doing and that is going to translate to dollars. I'm a fan of the 318 but your 425 horse target is going to be up there in the rpm range unless you stroke it. The 360 is going to get you there easier and develop more torque an therefore if you are looking for milage you can run a taller gear and still get adequate performance. There are sacrifices each way but I think a roller motor would be a good bet as suggested above. I'm building a 360 LA roller right now for street and strip use but my target of 400 horse is more attainable without sacrificing drivability.