Size of the bolt on the front lower pully that mounts to crank?

["Andrew B. Lundgren" <Lundgren@iname.com>]

Anyone know the size of the bolt on the front lower pully that bolts to the 
crank?  I need to regap my valves tonight and want to try using my big ratchet 
to turn the engine.   (That or jack up the rear end and put it in forth...)

Thanks!

Andrew Lundgren