Removed cleco from right pilot hole and use #30 drill bit as locating pin for drill guide block. Shimmed bushing with scotch tape to fit back into reamed guide block. Relocated block with bushing over drill bit and clamped in place. Removed drill bit/bushing, drilled hole out to 9/32" and reamed out to 5/16. Secured with temporary long bolt, using oversize nuts to shim out to threads. Replaced the long bolt with matching short bolt later.