YA , i gotta side with Henry.To alot of people ,the 305 heads seem too good to be true. But they are a lighter casting and easier cracked and with their smaller combustion chambers, they SOMETIMES, raise the compression ratio through the roof. Unless you have carefull engineered, or biult this motor to compensate for this , you will probably have more headaches than it's worth.
Just my opinion!
P.S. sorry to take the wind out of your sails ,but if you want a good reliable motor, sometimes its worth spending the extra $ .
Good luck