Really 2 issues ... 1 our heads wont handle the lift per Harley's engineering they will as Dawg states only handle up to a .550 lift. The second problem you have is the heads as they are, are not very efficient in velocity. They are approx 94 cc from the factory while the 103+ heads are 98cc from the factory with a higher lift and bigger intake port.
You will need to get headwork on the heads / rocker boxes (clearanced) if you want to handle a 650 lift. You will want to install the roller rockers if your over a 600 lift anyhow as a general rule of thumb.
The velocity is another issue most of the guys are welding up the chambers and building up the floors of the heads to get the velocity up in the heads while still trying to keep the CFM in the heads. The object there being to keep the CFM and add in the velocity while having a good squish.