1.158" (29.4) dia exhaust valve for
12G940 casting.
Our race valves are produced in EN214N stainless steel and require Manganese/Silicon bronze alloy valve guides. They are stellite tipped and have the triple collet groove and current valve head shapes. These valves are heat treated to eradicate wear from unleaded petrol.
As it is possible, even common, to swap one head for another on 1275 engines, be aware that if the head has been worked on previously, it may have oversize valves, it may have undersize if seats have been installed. Unless you are 100% sure what is in your cylinder head, it is a good idea to remove a valve for accurate measurement. There are two lengths used (nominally 3.52" & 3.57") three different keepers, (wide, narrow, and three-groove) and many different head diameters.
Note that 12G1316 (Smog-Type), all variations of the 12G940, and the latest CAM head castings all use the following 3.57" long valves.