I've seen A LOT of posts about making HP with a 318-So why is it so ???
I ran a 318 in my dart temporarily with the Summit manual trans cam. Stock heads,with headers and 2 1/2 inch exhaust. It pulled nice for what it was. I had an old timer come up to me at a gas station and say it sounded good,and asked if it was a 340...( I had the 340 badges on the scoops) :)
I keep the 318s around because they direct swap with 340,same internal balance etc. I think the only thing you need is the different motor mount brackets,everything else direct swaps.