The take off springs from most aluminum heads do work good for something like that.
Comp 911-15s are probably good for you. Anything else over 300 open load should be pretty OK. You could go higher, especially if you want to RPM the engine pretty tight, just remember higher spring pressures are tougher on the cam. One of the benefits to the Purpleshafts though is that the ramps were designed a long time ago. Guys will poo poo on them for not being a modern lobe, but they require less spring pressure and are less susceptible to getting wiped out.
Last edited by GTX MATT; 03/28/14 12:04 PM.