Is it OK to use a 3.910 gasket with a 3.098 bore size.? Should the gasket size be a certain amount larger than the bore size?

 

Don't forget there is a slight flare at the top of the cylinder so you can't go by the bore of the cylinder. You also need to measure chamber width as that may control gasket size. You need to make sure there is a little gap to the fire ring.

 

I agree totally!