390 vs 408

Like someone else said the 340/360 bore will un shroud the intake valve and help the engine breath a little better. The difference in cubic inches is not really that big a deal. But if the original poster is over seas, on a budget, and already has a good 318 block I think he would be happy to build a 390. Now if he has money to burn by all means pick up a 360 block and get the advantage of the larger bore.