Guess that depends on the rockers you got. DJ-2103 rockers from ARC require 5.160" rods, for instance. Running what will end up being a 404 lift with those ratio rockers I assume/hope you are not building a Hemi as that WILL coil bind without relief cuts and knock the stock piston regardless. Personally, I'd also look at getting into stainless or chrome moly push rods, switch to billet tappets and stainless valves because of the 32 lb springs and extra heat.
While I haven't gotten around to doing anything to my predator as I'm still researching and putting together a parts list, mine is a Hemi and I've run across the lift problems in my research.
And welcome to OldMiniBikes.