fuel line ?

Stock 340 hook the 3/8 lines up the the stock pump you will be just fine.

If you decide to go with the 3/8 lines on the carter pump you will have to run a regulator to dial the fuel pressure down, mine made 10 psi.

http://www.summitracing.com/parts/crt-m6270/overview/make/plymouth



I have this pump on my modified 340 and it work great.

http://www.summitracing.com/parts/crt-m6866/overview/make/plymouth