Take off the bottom clamp from the piston con rod (arm). These are not needed.



There should still be 2 bolts on the con rod (arm). One of these we will use as the bottom positioning bolt, the other one however needs to be punched out - its a simple hammer job.



This should leave a hole which can be used with an appropriate sized bolt to connect to the original head bolt hole on the engine block. (I think I had to enlarge this hole slightly to get the correct size bolt through).



(Note: In the photos you will see that I used threaded bar and a nut, but I think a bolt would be better. Also if I did it again I would grind a little of the arm adjacent to the top of this hole so that the bolt sat completely flat)



On one side this will leave the bottom bolt aligned with a section of cooling chamber. If you enlargen this slightly, then it can be used as a locating bolt. on the other side a new hole will have to be drilled. Again, this can be used as a locating bolt with the original piston con rod bolt.



Do this for 4 pistons (or 8 if you really wanted to!?).



(Additional note: You might be able to see from some of the pictures that there is not quite enough play in the pistons for the heads to sit flat, so if I was going to do this again I would at this point grid a little of the inside of the piston head or a little of the arm so that the piston heads can sit flat.)