I've got a 1973 mopar with a tired number matching 318. Running a built 904. LA motors are getting harder and harder to find, but magnums are readily available. I want something around 320-350 hp. I hear it's alot easier to get with magnum motors. I know factory heads on mags are bad and the cam will need to be changed to a long snout or use a kit to create a centric on cam to run mechanical fuel Pump. Who has done this build or swap. Is it pretty simple and everything bolt up or should I just keep. Looking for a LA 360 to build.