that looks fun to ride . so what about apex seals i would think somthing like that would be long gone
It is definitely the most fun sled to ride so far for any of my vintage projects.
funny thing about the apex seals, they supposedly were the weak point in these engines but after taking apart over a dozen of these 303's and then building over 8 back up i have only found one that had apex seals under the sachs tolerance.
there is a misprint in the cat manual. the seals start at 6.0mm and sachs says they can wear down to 4.5mm so -1.5mm of wear. cat misprinted it as new seal spec of 0.236" +0 - 0.015"making the lower limit of 0.221 or 5.62mm.
looks like an old metric to standard conversion error to me. the side seals and springs have all been well in spec in every one ive worked on, a couple had bad damage from ingesting something and most show wear on the bare aluminum side plates but those are fixable.