What year is your 340, is it a 72.5 or a 73? All of 'em prior to that were internal so your choice is gonna be limited if your swinging that big old cast crank 340 damper around. FD's are neutral balanced so you cannot be using any current balance weight on the nose as it will be replaced with a neutral FD balancer. Some others include bolt on weights but they are not fluid. Pioneer and Pro-Comp come to mind but the 2 weights are for 360 and 5.9 Magnums IIRC.
