The ones on my 12G1316 (MG with air injection ports) hear were 5/16-24 x 1.5" Hal On Tue, Mar 17, 2009 at 12:48 PM, Jim F. <jimndi at frontiernet.net> wrote: > Does anyone off hand know the size of the int / exh studs on the 1275 head? > Are they 5/16 fine both ends??