Are there roller lifters and cam that I can drop in my 340 with no modifications

WRONG. Stop living in the past and pay attention. http://www.mrlperformance.com/
They only show solid roller lifters on that web site. The offset pushrod holes don't negate the need for real short custom pushrods. After doing tons of research, I like the Hughes, if you want hydraulics. You will want adjustable rocker arms. They don't need to be roller rockers, but I have not recently seen new adjustable rockers for sale that are not rollers. Also, one thing nobody mentioned yet is that as far as I know all non-Magnum heads will need to have the pushrod holes elongated to clear the more angled pushrods. That's probably a job for a machine shop, for most of us. Well, you have to take the heads off anyways to install the lifters, so that might also be something else to think about.