if you are really cheap like me you could get some springs/retainers from a GM 3.1 or 3.4 motor in the junkyard. with the lift you have, they will probably be at their limit. here they are on my heads, the 4 closest in the pic are the stock magnum springs, the other 4 are from a 3.4 motor. the redrilling jig i made on the other head too.