Faren

Hi there, Can anyone tell the thread pitch of the bolts that secure the boot from the carbs to the intake manifold? I've had a world of pain with one of these shearing off leaving the bolt stem stuck inside the cylinder head which has been drilled, but still needs to be re-tapped and I don't have a pitch guage to check the pitch to order the right tap. I know the bolts are metric 10mm. Any help would be greatly received.