You want to get a bottom tap in 12 X 1. 75. After your head is removed tap the holes all the way to the block bottom. Then clean all the holes out very good with a magnet, air, and brake clean.
The head should be installed and the studs installed in each hole dry. Then back the stud off the bottom of the block 1/3-1/2 turn. The nuts, washers, and stud thread tops should be liberally coated in ARP lube. Use the Cummins torque sequence... ... . Here is where there are difference between if you o-ring/fire-ring or are just installing.
WIth o-rings/fire-rings we torque 20-40-60-80-96 start motor and let warm completely. Shut down and let cool about 4 hours with hood shut. Then retorque to 110. In one week we then torque to 125. In about 30 days we torque again to 125.
With a standard gasket we just take then straight to 125 and do a retorque in a week to 10 days. Also the Cummins number for the marine gasket is as follows:
. 020 over 3283339
. 010 over 3283337
stock 3283335
Hope this helps, if you have any questions please feel free to phone.
Doug Smith