I agree with firestone.
The Merlin 540 is one AWSOME motor, and if its been tweaked properly.....man 'o man!
Here's a link to the "factory" motors to help you to compare what you have with what is known.
I'm seriously looking at the 509 iron head myself. Even though its their "base" motor, I don't see how you can beat the price for what you receive!
P.S. - I have a friend who has relatives in the Netherlands, are you related to any Puerto Ricans?!!!