http://forums.500cid.com/showthread.php?p=7713 Pay attention to what these guys have to say about valve springs. Also, remember that this motor was built with 10.5:1 static compression ratio and was produced at a time when we had 100+ octane fuel available down at the corner gas station. The fuel contained tetraethyl lead, so hard valve seats were not necessary. There is no lead in today's pump gas, so some provision will have to be made to install hardened exhaust valve seats in the heads or just run it without seats and watch the valves grind down into the heads. Let me explain about lead and valve seats. You know when you weld or solder a joint, the joint must be dry and clean. There is a tendency of the valve to weld to the seat in little spots as the motor runs. Then when the valve comes up off the seat, it tears out a little piece of the seat. This is what causes the valve to grind down into the seat with unleaded fuel and soft seats. The lead in the fuel we used to get "dirtied-up" the seat so that this welding of the valve to the seat could not take place.
Heres a Bonus for you cadillac guys.Stock cams are retarded 10 degrees from factory. Put a degree wheel on it and adjust...
actually it looks like i may have landed a 1969 cadillac for my 331. sheesh my balls are getting cut off tonight when the old lady finds out
Well, yes and no. Cads are high nickle castings and inserts are not needed. My '68 is built with parts and advice from MTS, from whence that info comes, and they seem to know more than I do about 'em. My '472 sounds pretty wicked to, I might add, although I dropped the compression to 10:1... Brian
its gravy- i put a 472 in my 81 Buick Regal, cuz i wanted the comp ratio more than i wanted to wait to find a 500 incher. More torque than you'll know what to do with. I still have the pan and hi-po oil pump needed to put one in any non caddy. Do NOT bother with hardened valve seats on caddy heads. Hardened valve seats are made from nickel stellite. Caddy heads of the era had very high nickel content. I've been told by numerous caddy guys not to install them unless the seats need repair. Mine never took a beating. You can juggle stock parts and get 7:1 up to 12.5:1 comp ratio. stock valve train hates rpm but you wont need her to rev.
When you start swapping this motor into your Cad, repost here how it goes. My buddy has a '55 Coupe and I am trying to talk him into a bigger caddy motor (it is motorless now).
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