fyi, hellwig makes a bunch of bars for 67~72 and several for 73~76 and they have all manner of different mount styles.
there is a bar out there that will work with whatever hodge-podge of parts you have cooking. it may be hellwig, it may be stock, it may be somebody else. it may or may not require new tabs be welded on. but there is one out there that will work and likely it's hellwig.