Cast crank,external balanced 340 balancer/damper is on the right.
Steel crank internally balanced 340 & all LA 318's is on the left.
A bigger counterweight with no writing, or a recessed, machined out area part way around the outer ring, will be for an LA 360.
If you do find a V-8 904 transmission, look for these variances:
* 1967 and older transmissions used a small snout converter which also had a different spline count. They do not interchange with 1968 & newer converters.
* Lock-up converters started in the late '70's/early '80's. The tip of the trans splines is machined smooth about 3/4". They take their own, special, lock-up converter & don't interchange with "regular" converters.