Front dual disc
 

Hi- Need some help. I have a 76 FLH with 76 style 40 spoke rims. The original front end had the single banana caliper. I am installing showa sliders and tubes with dual calipers. (84-99 style) I need 11.5" rotors and are noticing most are drilled for 5/16 bolts, not 3/8 like my 76 style hubs have.
Is the bolt pattern the same? Can I just drill them out or will the 84-99 rear rotor work? Thanks

You can drill them out, just make sure whichever bolts you use have a low profile head to be clear of everything when the wheel turns.