Smog Mount/Alternator Relocation

[DatsunRoadster <69roadster@comcast.net>]

We are looking at relocating the alternator on a '69 back to the 
original position (smog pump) to get it away from the heat of the 
header.  We have the mounting brackets, but do not have the bolts that 
go into the block.

Does anyone know the size for these bolts (length, thickness and 
threading) ?  Any ideas on where to get some if they wouldn't be 
available in a local hardware store....

Thanks!

-Scott