All mopar parts drag car, give me some feedback.
If you use the 340 cam, be sure to get the 68 4-spd cam and also the valve springs to go with it. It used to be available from Mopar Performance, but I also think comp cams reproduces it.
You might also want to bump up the compression a little by decking the block. I am sure someone else can help with how much.
Good luck with your project, sounds like fun!