Ok guys, Im the one that just got the 1967 Fleetwood Brougham. I posted before about where to find parts, how to fix my turn signal indiactors....and so on. I got the heads off of my 429, and found the source of my oil usage and plug fouling. Crumbled umbrella seals, and valve guides that are so worn, you can wiggle the bare valves in the guide and feel the play (back and forth, click, click). Also most of the valves were coated down the entire stem with fresh, wet, oil. So I found the culprit. Upon lifting the heads off, a little coolant went into each of the cylinders. Left over coolant in the head. Rather than clean it up quickly, I let it sat. To see if my rings would hold the liquid for any length of time. I came back 4 hours later and all of the cylinders were just as full as I left them. There is also very minimal cylinder wear. There is a ridge at the top of the cylinder that I would imagine to be about .005" I am an aircraft machinist by trade, so I am pretty good at guessing surface finish (rA), and dimensions. I took the heads apart, drove out the cast iron valve guides, and had the local auto shop grind the valves and install hardened valve seats, check for cracks and such, they came out great. These things I cannot do at home, so I let the pros do that, but I can do the rest and save a little dough. So I am ready to buy new valve guides and valve seals. Being that this car was meant for Leaded gas, and it now uses unleaded. What type of valve guides do I need to buy? Nickel bronze? Cast iron again? I want to get the right guides, what do you guys think?