I have 2 mercury "tower of power" 1500's i would like to trade out...one motor is a 1977 and the other is a 1975 (if i remember correctly)...the 1975 has been recently rebuilt (less than 20 hours on it)...both motors are in excellent condition from top to bottom, serviced annually and well taken care of...these motors are top notch...both have completely rebuilt trim pumps and cylinders (done by a person that knows these systems inside and out..that would be ME!)....both motors, controls and trim systems ready to bolt on and go...i would like to trade them for a yamaha V6 150....anybody have any ideas or tips on how best to accomplish this...i know that the readers here on iboats have great minds and come up with great ideas...im looking for members input on this! Thanks!