rollor cam in 340 ?

The one thing to watch out for on a 340, is the lifter bores. If you decide to go with hydraulic roller lifters, make sure to check the top of the lifter bores and make sure they don't have too much taper. The taper will expose the lifter oiling band and cause the lifters to not pump up. This is mostly a 340 issue. The 360 blocks from the mid 70's are cast a little different and not as prone to this issue. If you go with solid roller lifter, no worries.