The only thing I am thinking is that the 1340 core will not accept a 2800 cylinder... so, you do one of two things... remake the core (expensive) or you modify the 1340 core (risky) to accept 2800 jugs.... That done, u will need to replace the crankshaft, and piston rods, as the tourques and force will be different, not to mention the piston throw. I think you are think of the 1820 mod, but would be interested to see what you can find out if you would look it up.