I have a 468 with Merlin iron heads, 731 Crane Cam, 9.3 to 1 compression 750 Holley, MSD ignition and Eddie Marine Exhausts. The builder put MR43T AC plugs in it and set the timing at 35 degrees. I need to replace the plugs and I am not sure what they are supposed to be gapped at. Any advice?

I gap mine at .035 but you'll probably get varying opinions on this subject.

.035 but with the msd and no blower you might see a slight power gain by opening them up .010 at a time,Smitty