some heads on vehicles has square springs for the valves but hardly any and any i did see where very very very old engines .

i did ask my boss but i can't honestly remember what he said as it was many years ago.

i do know some engine builders were speccing oval wire springs as explained here New wire shapes and configurations have also changed spring selection. Coil spring wire used to be round; now (although more costly), some springs use ovate (oval-shaped) wire. An ovate wire gives you more spring in a given amount of space, which means that at the same installed height, an ovate wire can handle more lift than an old-school round-wire spring before stacking solid.


so would an oval spring be better in shorter stroke actions ?