Well, I pulled, cleaned & measured all the valves off my bad set of vortecs and here's what I found. ALL intake valves are a bit shorter than the exhaust valves. 4.88" vs. 5.91". The lock groove to tip is ALSO shorter on the intake valves. .260" vs. .290". Looks like I can use all the exhaust valves but will have to purchase new Manley intake valves. I wonder what the reasoning was for the valve variation? This would make the valve FACE to lock groove identical. Hardened tip inserts, perhaps?