A little info back to the group,

I came across the following valve springs and retainers from Crane Cams that increase lift clearance on Vortec heads without the need to machine anything.

They are Crane Cams, PN: 10309-1 Springs and Retainers. About $160.00 for a set of 16.

According to the Sallee Chevrolet site these are good for up to .550 lift.

Probably not the end all solution for the more radical amoung us but for those that want more cam than the .450 lift limitation of the stock vortec head allows, these may be a cost effective solution.

Anyway - there ya go!