I want more Hp for my 318

As far as headers go, they all stink real bad except if you decide to pay some much bigger price tags for ethier Doug's or TTI headers, and there still a pain, but at least you won't smash 3 out of 4 tubes on the first speed bump.

The 340 and 360 are small block engines, they both use or can use etier 904 or 727 tranny's. Just realize that there is a big block and /6 trans and they can not be used on a small block.
(One few things I can't stand about a MoPar)

Just have the tranny build for the intended power level if your going to be makeing a bunch.'

The fuel line at 5/16 can actually feed a good bit of power. An upgrade to a 3/8th's line is probably not going to be needed, but a good idea if you start searching for big power. Stainless steel line is the only type I'd look at.