Larry,
If the studs are original they will almost certainly be stretched, possibly corroded, and undoubtedly weakened. Modern high tensile bolts will tolerate a higher torque than original studs.
Modern (asbestos free) gaskets are not as compliant as the original c&a sandwich and can therefore require a little more torque to get a good seal.
My preference is to remove the studs, plug-tap the holes to full drilled depth (the original threads often stop short of the bottom of the hole) and use the longest possible bolts (with HT washers under the heads) to suit the full hole depth(s) and give maximum purchase .
To facilitate assembly, cut a screwdriver slot in the end of two appropriate lengths of studding and place them, one at each end of the block, diagonally opposite one another. This will ensure the gasket stays correctly located as the Head is lowered into position. The studding can then be removed with a screwdriver and replaced with bolts once a few of the other bolts are in place.
B…
Larry Lewis
Bernie