Ford: 1989 F250 Oil leak into cylinders, block fords, valve seals

Question
My 460 7.5L is leaking oil fouling the spark plugs, almost a quart per tank with nothing on the ground. this truck is driven about once a month with only 83K total. The Ford dealer thinks it is valve seals and wants $5K for a new engine. Does the diagonsis sound right and wouldn't I just have someone replace the seal?

Answer
Kurt, the first thing you have to do is determine where the leak is coming from.  Valve seals are a fairly easy fix, and they are also easy to diagnose.  Just remove the valve covers and look at them.  If they are pouring that much oil into the cylinder, then the valve seals will probably be completely gone, or cracked so bad that you can see with the naked eye.  You can also take a small screwdriver and push on them.  They should be "spongy."  If they are hard or brittle, then this is likely the cause.  You can do the job yourself with a couple of tools from the parts store.  A shadetree mechanic would probably do the job for around 150 dollars.  If the valve seals look good, then your problem is likely to be the piston rings.  If it is the piston rings, then you might as well rebuild the engine, as you will have to take the motor half way apart to fix the problem.  However, this will still cost less than 5 thousand dollars.  I know that I would rebuild a 460 for around 1000 dollars in labor, plus parts.  That is expensive, but I always take the block and heads to a machinist and have them bored, shaved and a valve job.  If I were you, I would look at the valve seals.  Big block fords seem to have an issue with dried out valve seals.  Then again, the valve seals are also 18 years old.  Good luck,   Jason