Michael Morse of 650 Central recommends the "heavy duty" rod kits from Mike's XS for hopped up 447 motors (the rods themselves are the same as the standard version but with heavier bearings). I've used them for quite a few years--good equipment, Japanese made, decent price, might be the same stuff Heiden sells. If you want to spend a little more, Wiseco Hot Rods are an option. If you want to spend a lot more, there's Carillo, Falicon, and whoever makes high end racing components on your side of the water. Whatever you use, have the crank welded; flywheels have a nasty tendency to separate in hopped up motors or in any motor after reassembly. If you want to minimize vibration, have the rods and pistons beam balanced before assembly and have the crank trued as close as possible to zero detectable runout at the journals.