There was a similar question about timing a 235 a few days ago. Here is a link to the 1951 truck shop manual.

If the engine has many years of accumulated crud on the flywheel, finding the steel ball on the flywheel is not easy. Sometimes the dust cover on the bellhousing needs to be removed so that the forward face of the flywheel can be cleaned to reveal the steel ball. Not many engines are as clean as healingbear's.

Hoyt