Just picked up a 6.0 bare block for a steal! Problem is seller didn't know the year of it. How can I figure out which style head bolt this block takes since I don't have any of the original bolts? Which holes would have longer bolts? Which would have shorter bolts? If the was an earlier block! Need to get main studs ordered an would rather order the correct ones the first time!

 

Im not entirely sure, but I think one block will have all the threads near the top and one will have some deeper in the block.

 

Stick something small down in the big bolt holes, like a piece of wire. You are checking to see if they are all the same depth or some are different. That will tell you which ones you need.

 

Check the casting number and see what year it is.

 

The older blocks will have two longer bolts and deeper threaded holes for the uppermost outside corners (opposite the dowels). The newer blocks have all the same length.